Fix "ParserError: Multiple SPDX license identifiers found in source file"

DEBUG logging is turned ON
Running truffle-plugin-verify v0.5.4
Verifying SigMasterChef
Reading artifact file at /Users/lebedkin/programming/xsigma/truffle-tutorial/SigToken/build/contracts/SigMasterChef.json
Retrieving constructor parameters from https://api-rinkeby.etherscan.io/api?apiKey=XZIUUNJQ7JEC12C3FD8R3SWPCGHAUKQ4FQ&module=account&action=txlist&address=0x71694eE1B3D95885FF94202f631B942462fD6B08&page=1&sort=asc&offset=1
Constructor parameters retrieved: 0x0000000000000000000000006dd0ff86f0fc977fe18df3d5166d222338c76a060000000000000000000000008716d1e0bc3f7f9ec42d784ef95b1f776f067cbd0000000000000000000000008babd6c9c46ec434592d4e9a564fdf8878e3577600000000000000000000000000000000000000000000000000000000007a0753
Sending verify request with POST arguments:
{
  "apikey": "<I removed it for github post>",
  "module": "contract",
  "action": "verifysourcecode",
  "contractaddress": "0x71694eE1B3D95885FF94202f631B942462fD6B08",
  "sourceCode": "{\"language\":\"Solidity\",\"sources\":{\"/Users/lebedkin/programming/xsigma/truffle-tutorial/SigToken/contracts/SigMasterChef.sol\":{\"content\":\"// SPDX-License-Identifier: MIT\\n/**\\n * Fork of MasterChef https://etherscan.io/address/0xc2edad668740f1aa35e4d8f227fb8e17dca888cd#code\\n*/\\n// We intentional leave many variables with original sushi name\\n// so you could save time at diff comparison while verifying the code\\n\\npragma solidity 0.6.12;\\n\\nimport \\\"@openzeppelin/contracts/token/ERC20/IERC20.sol\\\";\\nimport \\\"@openzeppelin/contracts/token/ERC20/SafeERC20.sol\\\";\\nimport \\\"@openzeppelin/contracts/utils/EnumerableSet.sol\\\";\\nimport \\\"@openzeppelin/contracts/math/SafeMath.sol\\\";\\nimport \\\"@openzeppelin/contracts/access/Ownable.sol\\\";\\n// former SushiToken\\nimport \\\"./SigToken.sol\\\";\\n\\n\\ninterface IMigratorChef {\\n    // Perform LP token migration from legacy UniswapV2 to SushiSwap.\\n    // Take the current LP token address and return the new LP token address.\\n    // Migrator should have full access to the caller's LP token.\\n    // Return the new LP token address.\\n    //\\n    // XXX Migrator must have allowance access to UniswapV2 LP tokens.\\n    // SushiSwap must mint EXACTLY the same amount of SushiSwap LP tokens or\\n    // else something bad will happen. Traditional UniswapV2 does not\\n    // do that so be careful!\\n    function migrate(IERC20 token) external returns (IERC20);\\n}\\n\\n// MasterChef is the master of Sushi. He can make Sushi and he is a fair guy.\\n//\\n// Note that it's ownable and the owner wields tremendous power. The ownership\\n// will be transferred to a governance smart contract once SUSHI is sufficiently\\n// distributed and the community can show to govern itself.\\n//\\n// Have fun reading it. Hopefully it's bug-free. God bless.\\ncontract SigMasterChef is Ownable {\\n    using SafeMath for uint256;\\n    using SafeERC20 for IERC20;\\n\\n    // Info of each user.\\n    struct UserInfo {\\n        uint256 amount;     // How many LP tokens the user has provided.\\n        uint256 rewardDebt; // Reward debt. See explanation below.\\n        //\\n        // We do some fancy math here. Basically, any point in time, the amount of SUSHIs\\n        // entitled to a user but is pending to be distributed is:\\n        //\\n        //   pending reward = (user.amount * pool.accSushiPerShare) - user.rewardDebt\\n        //\\n        // Whenever a user deposits or withdraws LP tokens to a pool. Here's what happens:\\n        //   1. The pool's `accSushiPerShare` (and `lastRewardBlock`) gets updated.\\n        //   2. User receives the pending reward sent to his/her address.\\n        //   3. User's `amount` gets updated.\\n        //   4. User's `rewardDebt` gets updated.\\n    }\\n\\n    // Info of each pool.\\n    struct PoolInfo {\\n        IERC20 lpToken;           // Address of LP token contract.\\n        uint256 allocPoint;       // How many allocation points assigned to this pool. SUSHIs to distribute per block.\\n        uint256 lastRewardBlock;  // Last block number that SUSHIs distribution occurs.\\n        uint256 accSushiPerShare; // Accumulated SUSHIs per share, times 1e12. See below.\\n    }\\n\\n    // The SUSHI TOKEN!\\n    SigToken public sushi;\\n    // Dev address // here's it growthFund\\n    address public devaddr;\\n    // xSigma's sharedVault of investors\\n    address public sharedVault;\\n\\n    // 🐧 all this logic moved to totalReward()\\n    // // Block number when bonus SUSHI period ends.\\n    // uint256 public bonusEndBlock; \\n    // // SUSHI tokens created per block.\\n    // uint256 public sushiPerBlock;\\n    // // Bonus multiplier for early sushi makers.\\n    // uint256 public constant BONUS_MULTIPLIER = 10; // * moved to supplyFunction\\n\\n\\n    // The migrator contract. It has a lot of power. Can only be set through governance (owner).\\n    // IMigratorChef public migrator;\\n\\n    // Info of each pool.\\n    PoolInfo[] public poolInfo;\\n    // Info of each user that stakes LP tokens.\\n    mapping (uint256 => mapping (address => UserInfo)) public userInfo;\\n    // Total allocation points. Must be the sum of all allocation points in all pools.\\n    uint256 public totalAllocPoint = 0;\\n    // The block number when SUSHI mining starts.\\n    uint256 public startBlock;\\n    // reward time factor, the bigger it's the longer it take to distribute reward\\n    uint256 public rewardTimeFactor = 1;\\n\\n    event Deposit(address indexed user, uint256 indexed pid, uint256 amount);\\n    event Withdraw(address indexed user, uint256 indexed pid, uint256 amount);\\n    event EmergencyWithdraw(address indexed user, uint256 indexed pid, uint256 amount);\\n\\n    uint256 constant MIN_REWARD_TIME_FACTOR = 1;\\n    uint256 constant MAX_REWARD_TIME_FACTOR = 40;\\n\\n    function totalRewardAtBlock(uint256 atBlock) public view returns (uint256) {\\n        if (atBlock < startBlock) return 0;\\n        uint256 t = (atBlock - startBlock) / rewardTimeFactor;\\n        return sushi.maxRewardMintAfterBlocks(t);\\n    }\\n\\n    constructor(\\n        SigToken _sushi,\\n        address _devaddr,\\n        address _sharedVault,\\n    // uint256 _sushiPerBlock,\\n        uint256 _startBlock\\n    // uint256 _bonusEndBlock\\n    ) public {\\n        sushi = _sushi;\\n        devaddr = _devaddr;\\n        sharedVault = _sharedVault;\\n        // sushiPerBlock = _sushiPerBlock;\\n        // bonusEndBlock = _bonusEndBlock;\\n        startBlock = _startBlock;\\n    }\\n\\n    function poolLength() external view returns (uint256) {\\n        return poolInfo.length;\\n    }\\n\\n    // beware that chane of this parameter might break the contract\\n    function changeFactor(uint256 newFactor) public onlyOwner {\\n        require(MIN_REWARD_TIME_FACTOR <= newFactor && newFactor <= MAX_REWARD_TIME_FACTOR, \\\"Invalid time factor\\\");\\n        rewardTimeFactor = newFactor;\\n    }\\n\\n    // Add a new lp to the pool. Can only be called by the owner.\\n    // XXX DO NOT add the same LP token more than once. Rewards will be messed up if you do.\\n    function add(uint256 _allocPoint, IERC20 _lpToken, bool _withUpdate) public onlyOwner {\\n        if (_withUpdate) {\\n            massUpdatePools();\\n        }\\n        uint256 lastRewardBlock = block.number > startBlock ? block.number : startBlock;\\n        totalAllocPoint = totalAllocPoint.add(_allocPoint);\\n        poolInfo.push(PoolInfo({\\n        lpToken: _lpToken,\\n        allocPoint: _allocPoint,\\n        lastRewardBlock: lastRewardBlock,\\n        accSushiPerShare: 0\\n        }));\\n    }\\n\\n    // Update the given pool's SUSHI allocation point. Can only be called by the owner.\\n    function set(uint256 _pid, uint256 _allocPoint, bool _withUpdate) public onlyOwner {\\n        if (_withUpdate) {\\n            massUpdatePools();\\n        }\\n        totalAllocPoint = totalAllocPoint.sub(poolInfo[_pid].allocPoint).add(_allocPoint);\\n        poolInfo[_pid].allocPoint = _allocPoint;\\n    }\\n\\n    //    // Set the migrator contract. Can only be called by the owner.\\n    //    function setMigrator(IMigratorChef _migrator) public onlyOwner {\\n    //        migrator = _migrator;\\n    //    }\\n    //\\n    //    // Migrate lp token to another lp contract. Can be called by anyone. We trust that migrator contract is good.\\n    //    function migrate(uint256 _pid) public {\\n    //        require(address(migrator) != address(0), \\\"migrate: no migrator\\\");\\n    //        PoolInfo storage pool = poolInfo[_pid];\\n    //        IERC20 lpToken = pool.lpToken;\\n    //        uint256 bal = lpToken.balanceOf(address(this));\\n    //        lpToken.safeApprove(address(migrator), bal);\\n    //        IERC20 newLpToken = migrator.migrate(lpToken);\\n    //        require(bal == newLpToken.balanceOf(address(this)), \\\"migrate: bad\\\");\\n    //        pool.lpToken = newLpToken;\\n    //    }\\n\\n    // Return reward multiplier over the given _from to _to block.\\n    // function getMultiplier(uint256 _from, uint256 _to) public view returns (uint256) {\\n    //     if (_to <= bonusEndBlock) {\\n    //         return _to.sub(_from).mul(BONUS_MULTIPLIER);\\n    //     } else if (_from >= bonusEndBlock) {\\n    //         return _to.sub(_from);\\n    //     } else {\\n    //         return bonusEndBlock.sub(_from).mul(BONUS_MULTIPLIER).add(\\n    //             _to.sub(bonusEndBlock)\\n    //         );\\n    //     }\\n    // }\\n    // how much Sushi was minted from _from block to _to block\\n    // == sushiPerBlock * getMultiplier(_from, _to);\\n\\n    // View function to see pending SUSHIs on \\\"frontend\\\".\\n    function pendingSushi(uint256 _pid, address _user) external view returns (uint256) {\\n        // better name: currPoolInfo \\n        PoolInfo storage pool = poolInfo[_pid];\\n\\n        // better name: userOfCurrPool\\n        UserInfo storage user = userInfo[_pid][_user];\\n\\n        // Accumulated SUSHIs per share, times 1e12.\\n        uint256 accSushiPerShare = pool.accSushiPerShare;\\n\\n        // better name: total_staked_LpTokens_of_currPool \\n        uint256 lpSupply = pool.lpToken.balanceOf(address(this)); // how many LP_tokens staked in the MasterChef\\n\\n        // if currPool has any LpToken staked\\n        if (block.number > pool.lastRewardBlock && lpSupply != 0) {\\n            // // totalSushi minted / sushiPerBlock on (lastRewardBlock .. block.number]\\n            // uint256 multiplier = getMultiplier(pool.lastRewardBlock, block.number);\\n            // \\n            // // currPool's reward weight = pool.allocPoint / totalAllocPoint\\n            // // better name: sushiReward_for_currPool on (lastRewardBlock ... block.number]\\n            // uint256 sushiReward = multiplier.mul(sushiPerBlock).mul(pool.allocPoint).div(totalAllocPoint);\\n            //\\n            // accSushiPerShare = accSushiPerShare.add(sushiReward.mul(1e12).div(lpSupply));\\n\\n            // 🐧 we use different reward function, so instead the code above:\\n            uint256 totalSushiReward = totalRewardAtBlock(block.number).sub(totalRewardAtBlock(pool.lastRewardBlock));\\n            uint256 totalSushiRewardForPool = totalSushiReward.mul(pool.allocPoint).div(totalAllocPoint);\\n            accSushiPerShare = accSushiPerShare.add(totalSushiRewardForPool.mul(1e12).div(lpSupply));\\n        }\\n        return user.amount.mul(accSushiPerShare).div(1e12).sub(user.rewardDebt);\\n    }\\n\\n    // Update reward variables for all pools. Be careful of gas spending!\\n    function massUpdatePools() public {\\n        uint256 length = poolInfo.length;\\n        for (uint256 pid = 0; pid < length; ++pid) {\\n            updatePool(pid);\\n        }\\n    }\\n\\n    // Update reward variables of the given pool to be up-to-date.\\n    function updatePool(uint256 _pid) public {\\n        PoolInfo storage pool = poolInfo[_pid];\\n        if (block.number <= pool.lastRewardBlock) {\\n            return;\\n        }\\n        uint256 lpSupply = pool.lpToken.balanceOf(address(this));\\n        if (lpSupply == 0) {\\n            pool.lastRewardBlock = block.number;\\n            return;\\n        }\\n\\n        // // multiplier * sushiPerBlock = total sushi minted (pool.lastRewardBlock, block.number)\\n        // uint256 multiplier = getMultiplier(pool.lastRewardBlock, block.number);\\n\\n        // // poolWeight * total_minted\\n        // // better name: sushiReward_for_currPool on (pool.lastRewardBlock, block.number)\\n        // uint256 sushiReward = multiplier.mul(sushiPerBlock).mul(pool.allocPoint).div(totalAllocPoint);\\n\\n        // 🐧 we use different reward function, so instead the code above:\\n        uint256 totalSushiReward = totalRewardAtBlock(block.number) - totalRewardAtBlock(pool.lastRewardBlock);\\n        uint256 totalSushiRewardForPool = totalSushiReward.mul(pool.allocPoint).div(totalAllocPoint);\\n\\n        // 60% for Lps\\n        sushi.mint(address(this), totalSushiRewardForPool.mul(60).div(100));\\n        // 10% for growthFund\\n        sushi.mint(devaddr, totalSushiRewardForPool.div(10));\\n        // 30% are minted/unlock directly from reward token\\n        sushi.mint(address(sharedVault), totalSushiRewardForPool.mul(30).div(100));\\n\\n        pool.accSushiPerShare = pool.accSushiPerShare.add(totalSushiRewardForPool.mul(1e12).div(lpSupply));\\n        // \\n        pool.lastRewardBlock = block.number;\\n    }\\n\\n    // Deposit LP tokens to MasterChef for SUSHI allocation.\\n    function deposit(uint256 _pid, uint256 _amount) public {\\n        PoolInfo storage pool = poolInfo[_pid];\\n        UserInfo storage user = userInfo[_pid][msg.sender];\\n        updatePool(_pid);\\n        if (user.amount > 0) {\\n            uint256 pending = user.amount.mul(pool.accSushiPerShare).div(1e12).sub(user.rewardDebt);\\n            if(pending > 0) {\\n                safeSushiTransfer(msg.sender, pending);\\n            }\\n        }\\n        if(_amount > 0) {\\n            pool.lpToken.safeTransferFrom(address(msg.sender), address(this), _amount);\\n            user.amount = user.amount.add(_amount);\\n        }\\n        // I could do this instead: user.rewardDebt += pending\\n        user.rewardDebt = user.amount.mul(pool.accSushiPerShare).div(1e12);\\n        emit Deposit(msg.sender, _pid, _amount);\\n    }\\n\\n    // Withdraw LP tokens from MasterChef.\\n    function withdraw(uint256 _pid, uint256 _amount) public {\\n        PoolInfo storage pool = poolInfo[_pid];\\n        UserInfo storage user = userInfo[_pid][msg.sender];\\n        require(user.amount >= _amount, \\\"withdraw: not good\\\");\\n        updatePool(_pid);\\n        uint256 pending = user.amount.mul(pool.accSushiPerShare).div(1e12).sub(user.rewardDebt);\\n        if(pending > 0) {\\n            safeSushiTransfer(msg.sender, pending);\\n        }\\n        if(_amount > 0) {\\n            user.amount = user.amount.sub(_amount);\\n            pool.lpToken.safeTransfer(address(msg.sender), _amount);\\n        }\\n        user.rewardDebt = user.amount.mul(pool.accSushiPerShare).div(1e12);\\n        emit Withdraw(msg.sender, _pid, _amount);\\n    }\\n\\n    // Withdraw without caring about rewards. EMERGENCY ONLY.\\n    function emergencyWithdraw(uint256 _pid) public {\\n        PoolInfo storage pool = poolInfo[_pid];\\n        UserInfo storage user = userInfo[_pid][msg.sender];\\n        uint256 amount = user.amount;\\n        user.amount = 0;\\n        user.rewardDebt = 0;\\n        pool.lpToken.safeTransfer(address(msg.sender), amount);\\n        emit EmergencyWithdraw(msg.sender, _pid, amount);\\n    }\\n\\n    // Safe sushi transfer function, just in case if rounding error causes pool to not have enough SUSHIs.\\n    function safeSushiTransfer(address _to, uint256 _amount) internal {\\n        uint256 sushiBal = sushi.balanceOf(address(this));\\n        if (_amount > sushiBal) {\\n            sushi.transfer(_to, sushiBal);\\n        } else {\\n            sushi.transfer(_to, _amount);\\n        }\\n    }\\n\\n    // Update dev address by the previous dev.\\n    function dev(address _devaddr) public {\\n        require(msg.sender == devaddr, \\\"dev: wut?\\\");\\n        devaddr = _devaddr;\\n    }\\n}\"},\"/Users/lebedkin/programming/xsigma/truffle-tutorial/SigToken/contracts/SigToken.sol\":{\"content\":\"// SPDX-License-Identifier: MIT\\npragma solidity 0.6.12;\\n\\nimport \\\"@openzeppelin/contracts/token/ERC20/ERC20.sol\\\";\\nimport \\\"@openzeppelin/contracts/token/ERC20/ERC20Burnable.sol\\\";\\nimport \\\"@openzeppelin/contracts/access/Ownable.sol\\\";\\n\\n\\n// SushiToken with Governance.\\ncontract SigToken is ERC20, Ownable, ERC20Burnable {\\n    using SafeMath for uint256;\\n    //  Bitcoin-like supply system:\\n    //      50 tokens per block (however it's Ethereum ~15 seconds block vs Bitcoin 10 minutes)\\n    //      every 210,000 blocks is halving ~ 36 days 11 hours\\n    //      32 eras ~  3 years 71 days 16 hours until complete mint\\n    //      21,000,000 is total supply\\n    //\\n    //  i,e. if each block is about 15 seconds on average:\\n    //      40,320 blocks/week\\n    //      2,016,000 tokens/week before first halving\\n    //      10,500,000 total before first halving\\n    //\\n    uint256 constant MAX_MAIN_SUPPLY = 21_000_000 * 1e18;\\n\\n    // the first week mint has x2 bonus     = +2,016,000\\n    // the second week mint has x1.5 bonus  = +1,008,000\\n    //\\n    uint256 constant BONUS_SUPPLY = 3_024_000 * 1e18;\\n\\n    // so total max supply is 24,024,000 + 24 to init the uniswap pool\\n    uint256 constant MAX_TOTAL_SUPPLY = MAX_MAIN_SUPPLY + BONUS_SUPPLY;\\n\\n    // The block number when SIG mining starts.\\n    uint256 public startBlock;\\n\\n    uint256 constant DECIMALS_MUL = 1e18;\\n    uint256 constant BLOCKS_PER_WEEK = 40_320;\\n    uint256 constant HALVING_BLOCKS = 210_000;\\n    // uint265 constant INITIAL_BLOCK_REWARD = 50;\\n\\n    function maxRewardMintAfterBlocks(uint256 t) public pure returns (uint256) {\\n        // the first week x2 mint\\n        if (t < BLOCKS_PER_WEEK) {\\n            return DECIMALS_MUL * 100 * t;\\n        }\\n        // second week x1.5 mint\\n        if (t < BLOCKS_PER_WEEK * 2) {\\n            return  DECIMALS_MUL * (100 * BLOCKS_PER_WEEK + 75 * (t - BLOCKS_PER_WEEK));\\n        }\\n        // after two weeks standard bitcoin issuance model https://en.bitcoin.it/wiki/Controlled_supply\\n        uint256 totalBonus = DECIMALS_MUL * (BLOCKS_PER_WEEK * 50 + BLOCKS_PER_WEEK * 25);\\n        assert(totalBonus >= 0);\\n        // how many halvings so far?\\n        uint256 era = t / HALVING_BLOCKS;\\n        assert(0 <= era);\\n        if (32 <= era) return MAX_TOTAL_SUPPLY;\\n        // total reward before current era (mul base reward 50)\\n        // sum : 1 + 1/2 + 1/4 … 1/2^n == 2 - 1/2^n == 1 - 1/1<<n == 1 - 1>>n\\n        // era reward per block (*1e18 *50)\\n        if (era == 0) {\\n            return totalBonus + DECIMALS_MUL* 50 * (t % HALVING_BLOCKS);\\n        }\\n        uint256 eraRewardPerBlock = (DECIMALS_MUL >> era);\\n        //        assert(0 <= eraRewardPerBlock);\\n        uint256 bcReward = (DECIMALS_MUL + DECIMALS_MUL - (eraRewardPerBlock<<1) ) * 50 * HALVING_BLOCKS;\\n        //        assert(0 <= bcReward);\\n        // reward in the last era which isn't over\\n        uint256 eraReward = eraRewardPerBlock * 50 * (t % HALVING_BLOCKS);\\n        //        assert(0 <= eraReward);\\n        uint256 result = totalBonus + bcReward + eraReward;\\n        assert(0 <= result);\\n        return result;\\n    }\\n\\n    function maxRewardMintAtBlock(uint256 atBlock) public view returns (uint256) {\\n        if (atBlock < startBlock) return 0;\\n        uint256 t = atBlock - startBlock;\\n        return maxRewardMintAfterBlocks(t);\\n    }\\n\\n\\n    constructor(\\n        uint256 _startBlock,\\n        uint256 _tinyMint\\n    ) public ERC20(\\\"xSigma.fi\\\", \\\"XSIG\\\") {\\n        startBlock = _startBlock;\\n        // *option #1*\\n        // majority of the mining does to LPs via MasterChef,\\n        // so to prevent potential malicious actions of early LPs on DAO voting\\n        // 30% supply reserved for the RnD/team goes to the timeVault which has the same unlock/vesting strategy as mint\\n        // so the team has can vote using their not yet minted (locked/vested) tokens.\\n        // it means the team would have guaranteed majority at DAO voting for the first: 2 weeks and 12.6 hours\\n        //      0.3 * 24,024,000 - 0.3* supply(t) > 0.7 * supply(t)\\n        //      7,207,200 > supply(t)\\n        //      7,207,200 - 4,032,000[first week] - 3,024,000[second week] = 151,200 on the third week\\n        //      50/block on the 3rd week, 151,000 / 50 = 3,024 block ~ 12.6 hours\\n        //\\n        // _mint(msg.sender, MAX_TOTAL_SUPPLY*10/3);\\n\\n        // *option #2*\\n        // DAO would start working from 2nd week\\n        // dev needs a little of  SIG tokens for uniswap SIG/ETH initialization\\n        _mint(msg.sender, _tinyMint);\\n    }\\n\\n\\n\\n    /// @notice Creates `_amount` token to `_to`. Must only be called by the owner (MasterChef).\\n    function mint(address _to, uint256 _amount) public onlyOwner {\\n        _mint(_to, _amount);\\n        _moveDelegates(address(0), _delegates[_to], _amount);\\n    }\\n\\n    // Copied and modified from YAM code:\\n    // https://github.com/yam-finance/yam-protocol/blob/master/contracts/token/YAMGovernanceStorage.sol\\n    // https://github.com/yam-finance/yam-protocol/blob/master/contracts/token/YAMGovernance.sol\\n    // Which is copied and modified from COMPOUND:\\n    // https://github.com/compound-finance/compound-protocol/blob/master/contracts/Governance/Comp.sol\\n\\n    /// @dev A record of each accounts delegate\\n    mapping (address => address) internal _delegates;\\n\\n    /// @notice A checkpoint for marking number of votes from a given block\\n    struct Checkpoint {\\n        uint32 fromBlock;\\n        uint256 votes;\\n    }\\n\\n    /// @notice A record of votes checkpoints for each account, by index\\n    mapping (address => mapping (uint32 => Checkpoint)) public checkpoints;\\n\\n    /// @notice The number of checkpoints for each account\\n    mapping (address => uint32) public numCheckpoints;\\n\\n    /// @notice The EIP-712 typehash for the contract's domain\\n    bytes32 public constant DOMAIN_TYPEHASH = keccak256(\\\"EIP712Domain(string name,uint256 chainId,address verifyingContract)\\\");\\n\\n    /// @notice The EIP-712 typehash for the delegation struct used by the contract\\n    bytes32 public constant DELEGATION_TYPEHASH = keccak256(\\\"Delegation(address delegatee,uint256 nonce,uint256 expiry)\\\");\\n\\n    /// @notice A record of states for signing / validating signatures\\n    mapping (address => uint) public nonces;\\n\\n    /// @notice An event thats emitted when an account changes its delegate\\n    event DelegateChanged(address indexed delegator, address indexed fromDelegate, address indexed toDelegate);\\n\\n    /// @notice An event thats emitted when a delegate account's vote balance changes\\n    event DelegateVotesChanged(address indexed delegate, uint previousBalance, uint newBalance);\\n\\n    /**\\n     * @notice Delegate votes from `msg.sender` to `delegatee`\\n     * @param delegator The address to get delegatee for\\n     */\\n    function delegates(address delegator) external view returns (address) {\\n        return _delegates[delegator];\\n    }\\n\\n    /**\\n     * @notice Delegate votes from `msg.sender` to `delegatee`\\n     * @param delegatee The address to delegate votes to\\n     */\\n    function delegate(address delegatee) external {\\n        return _delegate(msg.sender, delegatee);\\n    }\\n\\n    /**\\n     * @notice Delegates votes from signatory to `delegatee`\\n     * @param delegatee The address to delegate votes to\\n     * @param nonce The contract state required to match the signature\\n     * @param expiry The time at which to expire the signature\\n     * @param v The recovery byte of the signature\\n     * @param r Half of the ECDSA signature pair\\n     * @param s Half of the ECDSA signature pair\\n     */\\n    function delegateBySig(address delegatee, uint nonce, uint expiry, uint8 v, bytes32 r, bytes32 s) external {\\n        bytes32 domainSeparator = keccak256(abi.encode(DOMAIN_TYPEHASH, keccak256(bytes(name())), getChainId(), address(this)));\\n        bytes32 structHash = keccak256(abi.encode(DELEGATION_TYPEHASH, delegatee, nonce, expiry));\\n        bytes32 digest = keccak256(abi.encodePacked(\\\"\\\\x19\\\\x01\\\", domainSeparator, structHash));\\n        address signatory = ecrecover(digest, v, r, s);\\n        require(signatory != address(0), \\\"SIG::delegateBySig: invalid signature\\\");\\n        require(nonce == nonces[signatory]++, \\\"SIG::delegateBySig: invalid nonce\\\");\\n        require(now <= expiry, \\\"SIG::delegateBySig: signature expired\\\");\\n        return _delegate(signatory, delegatee);\\n    }\\n\\n    /**\\n     * @notice Gets the current votes balance for `account`\\n     * @param account The address to get votes balance\\n     * @return The number of current votes for `account`\\n     */\\n    function getCurrentVotes(address account) external view returns (uint256) {\\n        uint32 nCheckpoints = numCheckpoints[account];\\n        return nCheckpoints > 0 ? checkpoints[account][nCheckpoints - 1].votes : 0;\\n    }\\n\\n    /**\\n     * @notice Determine the prior number of votes for an account as of a block number\\n     * @dev Block number must be a finalized block or else this function will revert to prevent misinformation.\\n     * @param account The address of the account to check\\n     * @param blockNumber The block number to get the vote balance at\\n     * @return The number of votes the account had as of the given block\\n     */\\n    function getPriorVotes(address account, uint blockNumber) external view returns (uint256) {\\n        require(blockNumber < block.number, \\\"SIG::getPriorVotes: not yet determined\\\");\\n\\n        uint32 nCheckpoints = numCheckpoints[account];\\n        if (nCheckpoints == 0) {\\n            return 0;\\n        }\\n\\n        // First check most recent balance\\n        if (checkpoints[account][nCheckpoints - 1].fromBlock <= blockNumber) {\\n            return checkpoints[account][nCheckpoints - 1].votes;\\n        }\\n\\n        // Next check implicit zero balance\\n        if (checkpoints[account][0].fromBlock > blockNumber) {\\n            return 0;\\n        }\\n\\n        uint32 lower = 0;\\n        uint32 upper = nCheckpoints - 1;\\n        while (upper > lower) {\\n            uint32 center = upper - (upper - lower) / 2; // ceil, avoiding overflow\\n            Checkpoint memory cp = checkpoints[account][center];\\n            if (cp.fromBlock == blockNumber) {\\n                return cp.votes;\\n            } else if (cp.fromBlock < blockNumber) {\\n                lower = center;\\n            } else {\\n                upper = center - 1;\\n            }\\n        }\\n        return checkpoints[account][lower].votes;\\n    }\\n\\n    function _delegate(address delegator, address delegatee) internal {\\n        address currentDelegate = _delegates[delegator];\\n        uint256 delegatorBalance = balanceOf(delegator); // balance of underlying SIGs (not scaled);\\n        _delegates[delegator] = delegatee;\\n\\n        emit DelegateChanged(delegator, currentDelegate, delegatee);\\n\\n        _moveDelegates(currentDelegate, delegatee, delegatorBalance);\\n    }\\n\\n    function _moveDelegates(address srcRep, address dstRep, uint256 amount) internal {\\n        if (srcRep != dstRep && amount > 0) {\\n            if (srcRep != address(0)) {\\n                // decrease old representative\\n                uint32 srcRepNum = numCheckpoints[srcRep];\\n                uint256 srcRepOld = srcRepNum > 0 ? checkpoints[srcRep][srcRepNum - 1].votes : 0;\\n                uint256 srcRepNew = srcRepOld.sub(amount);\\n                _writeCheckpoint(srcRep, srcRepNum, srcRepOld, srcRepNew);\\n            }\\n\\n            if (dstRep != address(0)) {\\n                // increase new representative\\n                uint32 dstRepNum = numCheckpoints[dstRep];\\n                uint256 dstRepOld = dstRepNum > 0 ? checkpoints[dstRep][dstRepNum - 1].votes : 0;\\n                uint256 dstRepNew = dstRepOld.add(amount);\\n                _writeCheckpoint(dstRep, dstRepNum, dstRepOld, dstRepNew);\\n            }\\n        }\\n    }\\n\\n    function _writeCheckpoint(address delegatee, uint32 nCheckpoints, uint256 oldVotes, uint256 newVotes) internal {\\n        uint32 blockNumber = safe32(block.number, \\\"SIG::_writeCheckpoint: block number exceeds 32 bits\\\");\\n\\n        if (nCheckpoints > 0 && checkpoints[delegatee][nCheckpoints - 1].fromBlock == blockNumber) {\\n            checkpoints[delegatee][nCheckpoints - 1].votes = newVotes;\\n        } else {\\n            checkpoints[delegatee][nCheckpoints] = Checkpoint(blockNumber, newVotes);\\n            numCheckpoints[delegatee] = nCheckpoints + 1;\\n        }\\n\\n        emit DelegateVotesChanged(delegatee, oldVotes, newVotes);\\n    }\\n\\n    function safe32(uint n, string memory errorMessage) internal pure returns (uint32) {\\n        require(n < 2**32, errorMessage);\\n        return uint32(n);\\n    }\\n\\n    function getChainId() internal pure returns (uint) {\\n        uint256 chainId;\\n        assembly { chainId := chainid() }\\n        return chainId;\\n    }\\n}\"},\"@openzeppelin/contracts/GSN/Context.sol\":{\"content\":\"// SPDX-License-Identifier: MIT\\n\\npragma solidity >=0.6.0 <0.8.0;\\n\\n/*\\n * @dev Provides information about the current execution context, including the\\n * sender of the transaction and its data. While these are generally available\\n * via msg.sender and msg.data, they should not be accessed in such a direct\\n * manner, since when dealing with GSN meta-transactions the account sending and\\n * paying for execution may not be the actual sender (as far as an application\\n * is concerned).\\n *\\n * This contract is only required for intermediate, library-like contracts.\\n */\\nabstract contract Context {\\n    function _msgSender() internal view virtual returns (address payable) {\\n        return msg.sender;\\n    }\\n\\n    function _msgData() internal view virtual returns (bytes memory) {\\n        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691\\n        return msg.data;\\n    }\\n}\\n\"},\"@openzeppelin/contracts/access/Ownable.sol\":{\"content\":\"// SPDX-License-Identifier: MIT\\n\\npragma solidity >=0.6.0 <0.8.0;\\n\\nimport \\\"../GSN/Context.sol\\\";\\n/**\\n * @dev Contract module which provides a basic access control mechanism, where\\n * there is an account (an owner) that can be granted exclusive access to\\n * specific functions.\\n *\\n * By default, the owner account will be the one that deploys the contract. This\\n * can later be changed with {transferOwnership}.\\n *\\n * This module is used through inheritance. It will make available the modifier\\n * `onlyOwner`, which can be applied to your functions to restrict their use to\\n * the owner.\\n */\\nabstract contract Ownable is Context {\\n    address private _owner;\\n\\n    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);\\n\\n    /**\\n     * @dev Initializes the contract setting the deployer as the initial owner.\\n     */\\n    constructor () internal {\\n        address msgSender = _msgSender();\\n        _owner = msgSender;\\n        emit OwnershipTransferred(address(0), msgSender);\\n    }\\n\\n    /**\\n     * @dev Returns the address of the current owner.\\n     */\\n    function owner() public view returns (address) {\\n        return _owner;\\n    }\\n\\n    /**\\n     * @dev Throws if called by any account other than the owner.\\n     */\\n    modifier onlyOwner() {\\n        require(_owner == _msgSender(), \\\"Ownable: caller is not the owner\\\");\\n        _;\\n    }\\n\\n    /**\\n     * @dev Leaves the contract without owner. It will not be possible to call\\n     * `onlyOwner` functions anymore. Can only be called by the current owner.\\n     *\\n     * NOTE: Renouncing ownership will leave the contract without an owner,\\n     * thereby removing any functionality that is only available to the owner.\\n     */\\n    function renounceOwnership() public virtual onlyOwner {\\n        emit OwnershipTransferred(_owner, address(0));\\n        _owner = address(0);\\n    }\\n\\n    /**\\n     * @dev Transfers ownership of the contract to a new account (`newOwner`).\\n     * Can only be called by the current owner.\\n     */\\n    function transferOwnership(address newOwner) public virtual onlyOwner {\\n        require(newOwner != address(0), \\\"Ownable: new owner is the zero address\\\");\\n        emit OwnershipTransferred(_owner, newOwner);\\n        _owner = newOwner;\\n    }\\n}\\n\"},\"@openzeppelin/contracts/math/SafeMath.sol\":{\"content\":\"// SPDX-License-Identifier: MIT\\n\\npragma solidity >=0.6.0 <0.8.0;\\n\\n/**\\n * @dev Wrappers over Solidity's arithmetic operations with added overflow\\n * checks.\\n *\\n * Arithmetic operations in Solidity wrap on overflow. This can easily result\\n * in bugs, because programmers usually assume that an overflow raises an\\n * error, which is the standard behavior in high level programming languages.\\n * `SafeMath` restores this intuition by reverting the transaction when an\\n * operation overflows.\\n *\\n * Using this library instead of the unchecked operations eliminates an entire\\n * class of bugs, so it's recommended to use it always.\\n */\\nlibrary SafeMath {\\n    /**\\n     * @dev Returns the addition of two unsigned integers, reverting on\\n     * overflow.\\n     *\\n     * Counterpart to Solidity's `+` operator.\\n     *\\n     * Requirements:\\n     *\\n     * - Addition cannot overflow.\\n     */\\n    function add(uint256 a, uint256 b) internal pure returns (uint256) {\\n        uint256 c = a + b;\\n        require(c >= a, \\\"SafeMath: addition overflow\\\");\\n\\n        return c;\\n    }\\n\\n    /**\\n     * @dev Returns the subtraction of two unsigned integers, reverting on\\n     * overflow (when the result is negative).\\n     *\\n     * Counterpart to Solidity's `-` operator.\\n     *\\n     * Requirements:\\n     *\\n     * - Subtraction cannot overflow.\\n     */\\n    function sub(uint256 a, uint256 b) internal pure returns (uint256) {\\n        return sub(a, b, \\\"SafeMath: subtraction overflow\\\");\\n    }\\n\\n    /**\\n     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on\\n     * overflow (when the result is negative).\\n     *\\n     * Counterpart to Solidity's `-` operator.\\n     *\\n     * Requirements:\\n     *\\n     * - Subtraction cannot overflow.\\n     */\\n    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {\\n        require(b <= a, errorMessage);\\n        uint256 c = a - b;\\n\\n        return c;\\n    }\\n\\n    /**\\n     * @dev Returns the multiplication of two unsigned integers, reverting on\\n     * overflow.\\n     *\\n     * Counterpart to Solidity's `*` operator.\\n     *\\n     * Requirements:\\n     *\\n     * - Multiplication cannot overflow.\\n     */\\n    function mul(uint256 a, uint256 b) internal pure returns (uint256) {\\n        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the\\n        // benefit is lost if 'b' is also tested.\\n        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522\\n        if (a == 0) {\\n            return 0;\\n        }\\n\\n        uint256 c = a * b;\\n        require(c / a == b, \\\"SafeMath: multiplication overflow\\\");\\n\\n        return c;\\n    }\\n\\n    /**\\n     * @dev Returns the integer division of two unsigned integers. Reverts on\\n     * division by zero. The result is rounded towards zero.\\n     *\\n     * Counterpart to Solidity's `/` operator. Note: this function uses a\\n     * `revert` opcode (which leaves remaining gas untouched) while Solidity\\n     * uses an invalid opcode to revert (consuming all remaining gas).\\n     *\\n     * Requirements:\\n     *\\n     * - The divisor cannot be zero.\\n     */\\n    function div(uint256 a, uint256 b) internal pure returns (uint256) {\\n        return div(a, b, \\\"SafeMath: division by zero\\\");\\n    }\\n\\n    /**\\n     * @dev Returns the integer division of two unsigned integers. Reverts with custom message on\\n     * division by zero. The result is rounded towards zero.\\n     *\\n     * Counterpart to Solidity's `/` operator. Note: this function uses a\\n     * `revert` opcode (which leaves remaining gas untouched) while Solidity\\n     * uses an invalid opcode to revert (consuming all remaining gas).\\n     *\\n     * Requirements:\\n     *\\n     * - The divisor cannot be zero.\\n     */\\n    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {\\n        require(b > 0, errorMessage);\\n        uint256 c = a / b;\\n        // assert(a == b * c + a % b); // There is no case in which this doesn't hold\\n\\n        return c;\\n    }\\n\\n    /**\\n     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),\\n     * Reverts when dividing by zero.\\n     *\\n     * Counterpart to Solidity's `%` operator. This function uses a `revert`\\n     * opcode (which leaves remaining gas untouched) while Solidity uses an\\n     * invalid opcode to revert (consuming all remaining gas).\\n     *\\n     * Requirements:\\n     *\\n     * - The divisor cannot be zero.\\n     */\\n    function mod(uint256 a, uint256 b) internal pure returns (uint256) {\\n        return mod(a, b, \\\"SafeMath: modulo by zero\\\");\\n    }\\n\\n    /**\\n     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),\\n     * Reverts with custom message when dividing by zero.\\n     *\\n     * Counterpart to Solidity's `%` operator. This function uses a `revert`\\n     * opcode (which leaves remaining gas untouched) while Solidity uses an\\n     * invalid opcode to revert (consuming all remaining gas).\\n     *\\n     * Requirements:\\n     *\\n     * - The divisor cannot be zero.\\n     */\\n    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {\\n        require(b != 0, errorMessage);\\n        return a % b;\\n    }\\n}\\n\"},\"@openzeppelin/contracts/token/ERC20/ERC20.sol\":{\"content\":\"// SPDX-License-Identifier: MIT\\n\\npragma solidity >=0.6.0 <0.8.0;\\n\\nimport \\\"../../GSN/Context.sol\\\";\\nimport \\\"./IERC20.sol\\\";\\nimport \\\"../../math/SafeMath.sol\\\";\\n\\n/**\\n * @dev Implementation of the {IERC20} interface.\\n *\\n * This implementation is agnostic to the way tokens are created. This means\\n * that a supply mechanism has to be added in a derived contract using {_mint}.\\n * For a generic mechanism see {ERC20PresetMinterPauser}.\\n *\\n * TIP: For a detailed writeup see our guide\\n * https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How\\n * to implement supply mechanisms].\\n *\\n * We have followed general OpenZeppelin guidelines: functions revert instead\\n * of returning `false` on failure. This behavior is nonetheless conventional\\n * and does not conflict with the expectations of ERC20 applications.\\n *\\n * Additionally, an {Approval} event is emitted on calls to {transferFrom}.\\n * This allows applications to reconstruct the allowance for all accounts just\\n * by listening to said events. Other implementations of the EIP may not emit\\n * these events, as it isn't required by the specification.\\n *\\n * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}\\n * functions have been added to mitigate the well-known issues around setting\\n * allowances. See {IERC20-approve}.\\n */\\ncontract ERC20 is Context, IERC20 {\\n    using SafeMath for uint256;\\n\\n    mapping (address => uint256) private _balances;\\n\\n    mapping (address => mapping (address => uint256)) private _allowances;\\n\\n    uint256 private _totalSupply;\\n\\n    string private _name;\\n    string private _symbol;\\n    uint8 private _decimals;\\n\\n    /**\\n     * @dev Sets the values for {name} and {symbol}, initializes {decimals} with\\n     * a default value of 18.\\n     *\\n     * To select a different value for {decimals}, use {_setupDecimals}.\\n     *\\n     * All three of these values are immutable: they can only be set once during\\n     * construction.\\n     */\\n    constructor (string memory name_, string memory symbol_) public {\\n        _name = name_;\\n        _symbol = symbol_;\\n        _decimals = 18;\\n    }\\n\\n    /**\\n     * @dev Returns the name of the token.\\n     */\\n    function name() public view returns (string memory) {\\n        return _name;\\n    }\\n\\n    /**\\n     * @dev Returns the symbol of the token, usually a shorter version of the\\n     * name.\\n     */\\n    function symbol() public view returns (string memory) {\\n        return _symbol;\\n    }\\n\\n    /**\\n     * @dev Returns the number of decimals used to get its user representation.\\n     * For example, if `decimals` equals `2`, a balance of `505` tokens should\\n     * be displayed to a user as `5,05` (`505 / 10 ** 2`).\\n     *\\n     * Tokens usually opt for a value of 18, imitating the relationship between\\n     * Ether and Wei. This is the value {ERC20} uses, unless {_setupDecimals} is\\n     * called.\\n     *\\n     * NOTE: This information is only used for _display_ purposes: it in\\n     * no way affects any of the arithmetic of the contract, including\\n     * {IERC20-balanceOf} and {IERC20-transfer}.\\n     */\\n    function decimals() public view returns (uint8) {\\n        return _decimals;\\n    }\\n\\n    /**\\n     * @dev See {IERC20-totalSupply}.\\n     */\\n    function totalSupply() public view override returns (uint256) {\\n        return _totalSupply;\\n    }\\n\\n    /**\\n     * @dev See {IERC20-balanceOf}.\\n     */\\n    function balanceOf(address account) public view override returns (uint256) {\\n        return _balances[account];\\n    }\\n\\n    /**\\n     * @dev See {IERC20-transfer}.\\n     *\\n     * Requirements:\\n     *\\n     * - `recipient` cannot be the zero address.\\n     * - the caller must have a balance of at least `amount`.\\n     */\\n    function transfer(address recipient, uint256 amount) public virtual override returns (bool) {\\n        _transfer(_msgSender(), recipient, amount);\\n        return true;\\n    }\\n\\n    /**\\n     * @dev See {IERC20-allowance}.\\n     */\\n    function allowance(address owner, address spender) public view virtual override returns (uint256) {\\n        return _allowances[owner][spender];\\n    }\\n\\n    /**\\n     * @dev See {IERC20-approve}.\\n     *\\n     * Requirements:\\n     *\\n     * - `spender` cannot be the zero address.\\n     */\\n    function approve(address spender, uint256 amount) public virtual override returns (bool) {\\n        _approve(_msgSender(), spender, amount);\\n        return true;\\n    }\\n\\n    /**\\n     * @dev See {IERC20-transferFrom}.\\n     *\\n     * Emits an {Approval} event indicating the updated allowance. This is not\\n     * required by the EIP. See the note at the beginning of {ERC20}.\\n     *\\n     * Requirements:\\n     *\\n     * - `sender` and `recipient` cannot be the zero address.\\n     * - `sender` must have a balance of at least `amount`.\\n     * - the caller must have allowance for ``sender``'s tokens of at least\\n     * `amount`.\\n     */\\n    function transferFrom(address sender, address recipient, uint256 amount) public virtual override returns (bool) {\\n        _transfer(sender, recipient, amount);\\n        _approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, \\\"ERC20: transfer amount exceeds allowance\\\"));\\n        return true;\\n    }\\n\\n    /**\\n     * @dev Atomically increases the allowance granted to `spender` by the caller.\\n     *\\n     * This is an alternative to {approve} that can be used as a mitigation for\\n     * problems described in {IERC20-approve}.\\n     *\\n     * Emits an {Approval} event indicating the updated allowance.\\n     *\\n     * Requirements:\\n     *\\n     * - `spender` cannot be the zero address.\\n     */\\n    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {\\n        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));\\n        return true;\\n    }\\n\\n    /**\\n     * @dev Atomically decreases the allowance granted to `spender` by the caller.\\n     *\\n     * This is an alternative to {approve} that can be used as a mitigation for\\n     * problems described in {IERC20-approve}.\\n     *\\n     * Emits an {Approval} event indicating the updated allowance.\\n     *\\n     * Requirements:\\n     *\\n     * - `spender` cannot be the zero address.\\n     * - `spender` must have allowance for the caller of at least\\n     * `subtractedValue`.\\n     */\\n    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {\\n        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, \\\"ERC20: decreased allowance below zero\\\"));\\n        return true;\\n    }\\n\\n    /**\\n     * @dev Moves tokens `amount` from `sender` to `recipient`.\\n     *\\n     * This is internal function is equivalent to {transfer}, and can be used to\\n     * e.g. implement automatic token fees, slashing mechanisms, etc.\\n     *\\n     * Emits a {Transfer} event.\\n     *\\n     * Requirements:\\n     *\\n     * - `sender` cannot be the zero address.\\n     * - `recipient` cannot be the zero address.\\n     * - `sender` must have a balance of at least `amount`.\\n     */\\n    function _transfer(address sender, address recipient, uint256 amount) internal virtual {\\n        require(sender != address(0), \\\"ERC20: transfer from the zero address\\\");\\n        require(recipient != address(0), \\\"ERC20: transfer to the zero address\\\");\\n\\n        _beforeTokenTransfer(sender, recipient, amount);\\n\\n        _balances[sender] = _balances[sender].sub(amount, \\\"ERC20: transfer amount exceeds balance\\\");\\n        _balances[recipient] = _balances[recipient].add(amount);\\n        emit Transfer(sender, recipient, amount);\\n    }\\n\\n    /** @dev Creates `amount` tokens and assigns them to `account`, increasing\\n     * the total supply.\\n     *\\n     * Emits a {Transfer} event with `from` set to the zero address.\\n     *\\n     * Requirements:\\n     *\\n     * - `to` cannot be the zero address.\\n     */\\n    function _mint(address account, uint256 amount) internal virtual {\\n        require(account != address(0), \\\"ERC20: mint to the zero address\\\");\\n\\n        _beforeTokenTransfer(address(0), account, amount);\\n\\n        _totalSupply = _totalSupply.add(amount);\\n        _balances[account] = _balances[account].add(amount);\\n        emit Transfer(address(0), account, amount);\\n    }\\n\\n    /**\\n     * @dev Destroys `amount` tokens from `account`, reducing the\\n     * total supply.\\n     *\\n     * Emits a {Transfer} event with `to` set to the zero address.\\n     *\\n     * Requirements:\\n     *\\n     * - `account` cannot be the zero address.\\n     * - `account` must have at least `amount` tokens.\\n     */\\n    function _burn(address account, uint256 amount) internal virtual {\\n        require(account != address(0), \\\"ERC20: burn from the zero address\\\");\\n\\n        _beforeTokenTransfer(account, address(0), amount);\\n\\n        _balances[account] = _balances[account].sub(amount, \\\"ERC20: burn amount exceeds balance\\\");\\n        _totalSupply = _totalSupply.sub(amount);\\n        emit Transfer(account, address(0), amount);\\n    }\\n\\n    /**\\n     * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.\\n     *\\n     * This internal function is equivalent to `approve`, and can be used to\\n     * e.g. set automatic allowances for certain subsystems, etc.\\n     *\\n     * Emits an {Approval} event.\\n     *\\n     * Requirements:\\n     *\\n     * - `owner` cannot be the zero address.\\n     * - `spender` cannot be the zero address.\\n     */\\n    function _approve(address owner, address spender, uint256 amount) internal virtual {\\n        require(owner != address(0), \\\"ERC20: approve from the zero address\\\");\\n        require(spender != address(0), \\\"ERC20: approve to the zero address\\\");\\n\\n        _allowances[owner][spender] = amount;\\n        emit Approval(owner, spender, amount);\\n    }\\n\\n    /**\\n     * @dev Sets {decimals} to a value other than the default one of 18.\\n     *\\n     * WARNING: This function should only be called from the constructor. Most\\n     * applications that interact with token contracts will not expect\\n     * {decimals} to ever change, and may work incorrectly if it does.\\n     */\\n    function _setupDecimals(uint8 decimals_) internal {\\n        _decimals = decimals_;\\n    }\\n\\n    /**\\n     * @dev Hook that is called before any transfer of tokens. This includes\\n     * minting and burning.\\n     *\\n     * Calling conditions:\\n     *\\n     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens\\n     * will be to transferred to `to`.\\n     * - when `from` is zero, `amount` tokens will be minted for `to`.\\n     * - when `to` is zero, `amount` of ``from``'s tokens will be burned.\\n     * - `from` and `to` are never both zero.\\n     *\\n     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].\\n     */\\n    function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual { }\\n}\\n\"},\"@openzeppelin/contracts/token/ERC20/ERC20Burnable.sol\":{\"content\":\"// SPDX-License-Identifier: MIT\\n\\npragma solidity >=0.6.0 <0.8.0;\\n\\nimport \\\"../../GSN/Context.sol\\\";\\nimport \\\"./ERC20.sol\\\";\\n\\n/**\\n * @dev Extension of {ERC20} that allows token holders to destroy both their own\\n * tokens and those that they have an allowance for, in a way that can be\\n * recognized off-chain (via event analysis).\\n */\\nabstract contract ERC20Burnable is Context, ERC20 {\\n    using SafeMath for uint256;\\n\\n    /**\\n     * @dev Destroys `amount` tokens from the caller.\\n     *\\n     * See {ERC20-_burn}.\\n     */\\n    function burn(uint256 amount) public virtual {\\n        _burn(_msgSender(), amount);\\n    }\\n\\n    /**\\n     * @dev Destroys `amount` tokens from `account`, deducting from the caller's\\n     * allowance.\\n     *\\n     * See {ERC20-_burn} and {ERC20-allowance}.\\n     *\\n     * Requirements:\\n     *\\n     * - the caller must have allowance for ``accounts``'s tokens of at least\\n     * `amount`.\\n     */\\n    function burnFrom(address account, uint256 amount) public virtual {\\n        uint256 decreasedAllowance = allowance(account, _msgSender()).sub(amount, \\\"ERC20: burn amount exceeds allowance\\\");\\n\\n        _approve(account, _msgSender(), decreasedAllowance);\\n        _burn(account, amount);\\n    }\\n}\\n\"},\"@openzeppelin/contracts/token/ERC20/IERC20.sol\":{\"content\":\"// SPDX-License-Identifier: MIT\\n\\npragma solidity >=0.6.0 <0.8.0;\\n\\n/**\\n * @dev Interface of the ERC20 standard as defined in the EIP.\\n */\\ninterface IERC20 {\\n    /**\\n     * @dev Returns the amount of tokens in existence.\\n     */\\n    function totalSupply() external view returns (uint256);\\n\\n    /**\\n     * @dev Returns the amount of tokens owned by `account`.\\n     */\\n    function balanceOf(address account) external view returns (uint256);\\n\\n    /**\\n     * @dev Moves `amount` tokens from the caller's account to `recipient`.\\n     *\\n     * Returns a boolean value indicating whether the operation succeeded.\\n     *\\n     * Emits a {Transfer} event.\\n     */\\n    function transfer(address recipient, uint256 amount) external returns (bool);\\n\\n    /**\\n     * @dev Returns the remaining number of tokens that `spender` will be\\n     * allowed to spend on behalf of `owner` through {transferFrom}. This is\\n     * zero by default.\\n     *\\n     * This value changes when {approve} or {transferFrom} are called.\\n     */\\n    function allowance(address owner, address spender) external view returns (uint256);\\n\\n    /**\\n     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.\\n     *\\n     * Returns a boolean value indicating whether the operation succeeded.\\n     *\\n     * IMPORTANT: Beware that changing an allowance with this method brings the risk\\n     * that someone may use both the old and the new allowance by unfortunate\\n     * transaction ordering. One possible solution to mitigate this race\\n     * condition is to first reduce the spender's allowance to 0 and set the\\n     * desired value afterwards:\\n     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729\\n     *\\n     * Emits an {Approval} event.\\n     */\\n    function approve(address spender, uint256 amount) external returns (bool);\\n\\n    /**\\n     * @dev Moves `amount` tokens from `sender` to `recipient` using the\\n     * allowance mechanism. `amount` is then deducted from the caller's\\n     * allowance.\\n     *\\n     * Returns a boolean value indicating whether the operation succeeded.\\n     *\\n     * Emits a {Transfer} event.\\n     */\\n    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);\\n\\n    /**\\n     * @dev Emitted when `value` tokens are moved from one account (`from`) to\\n     * another (`to`).\\n     *\\n     * Note that `value` may be zero.\\n     */\\n    event Transfer(address indexed from, address indexed to, uint256 value);\\n\\n    /**\\n     * @dev Emitted when the allowance of a `spender` for an `owner` is set by\\n     * a call to {approve}. `value` is the new allowance.\\n     */\\n    event Approval(address indexed owner, address indexed spender, uint256 value);\\n}\\n\"},\"@openzeppelin/contracts/token/ERC20/SafeERC20.sol\":{\"content\":\"// SPDX-License-Identifier: MIT\\n\\npragma solidity >=0.6.0 <0.8.0;\\n\\nimport \\\"./IERC20.sol\\\";\\nimport \\\"../../math/SafeMath.sol\\\";\\nimport \\\"../../utils/Address.sol\\\";\\n\\n/**\\n * @title SafeERC20\\n * @dev Wrappers around ERC20 operations that throw on failure (when the token\\n * contract returns false). Tokens that return no value (and instead revert or\\n * throw on failure) are also supported, non-reverting calls are assumed to be\\n * successful.\\n * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,\\n * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.\\n */\\nlibrary SafeERC20 {\\n    using SafeMath for uint256;\\n    using Address for address;\\n\\n    function safeTransfer(IERC20 token, address to, uint256 value) internal {\\n        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));\\n    }\\n\\n    function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {\\n        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));\\n    }\\n\\n    /**\\n     * @dev Deprecated. This function has issues similar to the ones found in\\n     * {IERC20-approve}, and its usage is discouraged.\\n     *\\n     * Whenever possible, use {safeIncreaseAllowance} and\\n     * {safeDecreaseAllowance} instead.\\n     */\\n    function safeApprove(IERC20 token, address spender, uint256 value) internal {\\n        // safeApprove should only be called when setting an initial allowance,\\n        // or when resetting it to zero. To increase and decrease it, use\\n        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'\\n        // solhint-disable-next-line max-line-length\\n        require((value == 0) || (token.allowance(address(this), spender) == 0),\\n            \\\"SafeERC20: approve from non-zero to non-zero allowance\\\"\\n        );\\n        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));\\n    }\\n\\n    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {\\n        uint256 newAllowance = token.allowance(address(this), spender).add(value);\\n        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));\\n    }\\n\\n    function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {\\n        uint256 newAllowance = token.allowance(address(this), spender).sub(value, \\\"SafeERC20: decreased allowance below zero\\\");\\n        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));\\n    }\\n\\n    /**\\n     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement\\n     * on the return value: the return value is optional (but if data is returned, it must not be false).\\n     * @param token The token targeted by the call.\\n     * @param data The call data (encoded using abi.encode or one of its variants).\\n     */\\n    function _callOptionalReturn(IERC20 token, bytes memory data) private {\\n        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since\\n        // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that\\n        // the target address contains contract code and also asserts for success in the low-level call.\\n\\n        bytes memory returndata = address(token).functionCall(data, \\\"SafeERC20: low-level call failed\\\");\\n        if (returndata.length > 0) { // Return data is optional\\n            // solhint-disable-next-line max-line-length\\n            require(abi.decode(returndata, (bool)), \\\"SafeERC20: ERC20 operation did not succeed\\\");\\n        }\\n    }\\n}\\n\"},\"@openzeppelin/contracts/utils/Address.sol\":{\"content\":\"// SPDX-License-Identifier: MIT\\n\\npragma solidity >=0.6.2 <0.8.0;\\n\\n/**\\n * @dev Collection of functions related to the address type\\n */\\nlibrary Address {\\n    /**\\n     * @dev Returns true if `account` is a contract.\\n     *\\n     * [IMPORTANT]\\n     * ====\\n     * It is unsafe to assume that an address for which this function returns\\n     * false is an externally-owned account (EOA) and not a contract.\\n     *\\n     * Among others, `isContract` will return false for the following\\n     * types of addresses:\\n     *\\n     *  - an externally-owned account\\n     *  - a contract in construction\\n     *  - an address where a contract will be created\\n     *  - an address where a contract lived, but was destroyed\\n     * ====\\n     */\\n    function isContract(address account) internal view returns (bool) {\\n        // This method relies on extcodesize, which returns 0 for contracts in\\n        // construction, since the code is only stored at the end of the\\n        // constructor execution.\\n\\n        uint256 size;\\n        // solhint-disable-next-line no-inline-assembly\\n        assembly { size := extcodesize(account) }\\n        return size > 0;\\n    }\\n\\n    /**\\n     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to\\n     * `recipient`, forwarding all available gas and reverting on errors.\\n     *\\n     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost\\n     * of certain opcodes, possibly making contracts go over the 2300 gas limit\\n     * imposed by `transfer`, making them unable to receive funds via\\n     * `transfer`. {sendValue} removes this limitation.\\n     *\\n     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].\\n     *\\n     * IMPORTANT: because control is transferred to `recipient`, care must be\\n     * taken to not create reentrancy vulnerabilities. Consider using\\n     * {ReentrancyGuard} or the\\n     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].\\n     */\\n    function sendValue(address payable recipient, uint256 amount) internal {\\n        require(address(this).balance >= amount, \\\"Address: insufficient balance\\\");\\n\\n        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value\\n        (bool success, ) = recipient.call{ value: amount }(\\\"\\\");\\n        require(success, \\\"Address: unable to send value, recipient may have reverted\\\");\\n    }\\n\\n    /**\\n     * @dev Performs a Solidity function call using a low level `call`. A\\n     * plain`call` is an unsafe replacement for a function call: use this\\n     * function instead.\\n     *\\n     * If `target` reverts with a revert reason, it is bubbled up by this\\n     * function (like regular Solidity function calls).\\n     *\\n     * Returns the raw returned data. To convert to the expected return value,\\n     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].\\n     *\\n     * Requirements:\\n     *\\n     * - `target` must be a contract.\\n     * - calling `target` with `data` must not revert.\\n     *\\n     * _Available since v3.1._\\n     */\\n    function functionCall(address target, bytes memory data) internal returns (bytes memory) {\\n      return functionCall(target, data, \\\"Address: low-level call failed\\\");\\n    }\\n\\n    /**\\n     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with\\n     * `errorMessage` as a fallback revert reason when `target` reverts.\\n     *\\n     * _Available since v3.1._\\n     */\\n    function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {\\n        return functionCallWithValue(target, data, 0, errorMessage);\\n    }\\n\\n    /**\\n     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],\\n     * but also transferring `value` wei to `target`.\\n     *\\n     * Requirements:\\n     *\\n     * - the calling contract must have an ETH balance of at least `value`.\\n     * - the called Solidity function must be `payable`.\\n     *\\n     * _Available since v3.1._\\n     */\\n    function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {\\n        return functionCallWithValue(target, data, value, \\\"Address: low-level call with value failed\\\");\\n    }\\n\\n    /**\\n     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but\\n     * with `errorMessage` as a fallback revert reason when `target` reverts.\\n     *\\n     * _Available since v3.1._\\n     */\\n    function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {\\n        require(address(this).balance >= value, \\\"Address: insufficient balance for call\\\");\\n        require(isContract(target), \\\"Address: call to non-contract\\\");\\n\\n        // solhint-disable-next-line avoid-low-level-calls\\n        (bool success, bytes memory returndata) = target.call{ value: value }(data);\\n        return _verifyCallResult(success, returndata, errorMessage);\\n    }\\n\\n    /**\\n     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],\\n     * but performing a static call.\\n     *\\n     * _Available since v3.3._\\n     */\\n    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {\\n        return functionStaticCall(target, data, \\\"Address: low-level static call failed\\\");\\n    }\\n\\n    /**\\n     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],\\n     * but performing a static call.\\n     *\\n     * _Available since v3.3._\\n     */\\n    function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {\\n        require(isContract(target), \\\"Address: static call to non-contract\\\");\\n\\n        // solhint-disable-next-line avoid-low-level-calls\\n        (bool success, bytes memory returndata) = target.staticcall(data);\\n        return _verifyCallResult(success, returndata, errorMessage);\\n    }\\n\\n    function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {\\n        if (success) {\\n            return returndata;\\n        } else {\\n            // Look for revert reason and bubble it up if present\\n            if (returndata.length > 0) {\\n                // The easiest way to bubble the revert reason is using memory via assembly\\n\\n                // solhint-disable-next-line no-inline-assembly\\n                assembly {\\n                    let returndata_size := mload(returndata)\\n                    revert(add(32, returndata), returndata_size)\\n                }\\n            } else {\\n                revert(errorMessage);\\n            }\\n        }\\n    }\\n}\\n\"},\"@openzeppelin/contracts/utils/EnumerableSet.sol\":{\"content\":\"// SPDX-License-Identifier: MIT\\n\\npragma solidity >=0.6.0 <0.8.0;\\n\\n/**\\n * @dev Library for managing\\n * https://en.wikipedia.org/wiki/Set_(abstract_data_type)[sets] of primitive\\n * types.\\n *\\n * Sets have the following properties:\\n *\\n * - Elements are added, removed, and checked for existence in constant time\\n * (O(1)).\\n * - Elements are enumerated in O(n). No guarantees are made on the ordering.\\n *\\n * ```\\n * contract Example {\\n *     // Add the library methods\\n *     using EnumerableSet for EnumerableSet.AddressSet;\\n *\\n *     // Declare a set state variable\\n *     EnumerableSet.AddressSet private mySet;\\n * }\\n * ```\\n *\\n * As of v3.3.0, sets of type `bytes32` (`Bytes32Set`), `address` (`AddressSet`)\\n * and `uint256` (`UintSet`) are supported.\\n */\\nlibrary EnumerableSet {\\n    // To implement this library for multiple types with as little code\\n    // repetition as possible, we write it in terms of a generic Set type with\\n    // bytes32 values.\\n    // The Set implementation uses private functions, and user-facing\\n    // implementations (such as AddressSet) are just wrappers around the\\n    // underlying Set.\\n    // This means that we can only create new EnumerableSets for types that fit\\n    // in bytes32.\\n\\n    struct Set {\\n        // Storage of set values\\n        bytes32[] _values;\\n\\n        // Position of the value in the `values` array, plus 1 because index 0\\n        // means a value is not in the set.\\n        mapping (bytes32 => uint256) _indexes;\\n    }\\n\\n    /**\\n     * @dev Add a value to a set. O(1).\\n     *\\n     * Returns true if the value was added to the set, that is if it was not\\n     * already present.\\n     */\\n    function _add(Set storage set, bytes32 value) private returns (bool) {\\n        if (!_contains(set, value)) {\\n            set._values.push(value);\\n            // The value is stored at length-1, but we add 1 to all indexes\\n            // and use 0 as a sentinel value\\n            set._indexes[value] = set._values.length;\\n            return true;\\n        } else {\\n            return false;\\n        }\\n    }\\n\\n    /**\\n     * @dev Removes a value from a set. O(1).\\n     *\\n     * Returns true if the value was removed from the set, that is if it was\\n     * present.\\n     */\\n    function _remove(Set storage set, bytes32 value) private returns (bool) {\\n        // We read and store the value's index to prevent multiple reads from the same storage slot\\n        uint256 valueIndex = set._indexes[value];\\n\\n        if (valueIndex != 0) { // Equivalent to contains(set, value)\\n            // To delete an element from the _values array in O(1), we swap the element to delete with the last one in\\n            // the array, and then remove the last element (sometimes called as 'swap and pop').\\n            // This modifies the order of the array, as noted in {at}.\\n\\n            uint256 toDeleteIndex = valueIndex - 1;\\n            uint256 lastIndex = set._values.length - 1;\\n\\n            // When the value to delete is the last one, the swap operation is unnecessary. However, since this occurs\\n            // so rarely, we still do the swap anyway to avoid the gas cost of adding an 'if' statement.\\n\\n            bytes32 lastvalue = set._values[lastIndex];\\n\\n            // Move the last value to the index where the value to delete is\\n            set._values[toDeleteIndex] = lastvalue;\\n            // Update the index for the moved value\\n            set._indexes[lastvalue] = toDeleteIndex + 1; // All indexes are 1-based\\n\\n            // Delete the slot where the moved value was stored\\n            set._values.pop();\\n\\n            // Delete the index for the deleted slot\\n            delete set._indexes[value];\\n\\n            return true;\\n        } else {\\n            return false;\\n        }\\n    }\\n\\n    /**\\n     * @dev Returns true if the value is in the set. O(1).\\n     */\\n    function _contains(Set storage set, bytes32 value) private view returns (bool) {\\n        return set._indexes[value] != 0;\\n    }\\n\\n    /**\\n     * @dev Returns the number of values on the set. O(1).\\n     */\\n    function _length(Set storage set) private view returns (uint256) {\\n        return set._values.length;\\n    }\\n\\n   /**\\n    * @dev Returns the value stored at position `index` in the set. O(1).\\n    *\\n    * Note that there are no guarantees on the ordering of values inside the\\n    * array, and it may change when more values are added or removed.\\n    *\\n    * Requirements:\\n    *\\n    * - `index` must be strictly less than {length}.\\n    */\\n    function _at(Set storage set, uint256 index) private view returns (bytes32) {\\n        require(set._values.length > index, \\\"EnumerableSet: index out of bounds\\\");\\n        return set._values[index];\\n    }\\n\\n    // Bytes32Set\\n\\n    struct Bytes32Set {\\n        Set _inner;\\n    }\\n\\n    /**\\n     * @dev Add a value to a set. O(1).\\n     *\\n     * Returns true if the value was added to the set, that is if it was not\\n     * already present.\\n     */\\n    function add(Bytes32Set storage set, bytes32 value) internal returns (bool) {\\n        return _add(set._inner, value);\\n    }\\n\\n    /**\\n     * @dev Removes a value from a set. O(1).\\n     *\\n     * Returns true if the value was removed from the set, that is if it was\\n     * present.\\n     */\\n    function remove(Bytes32Set storage set, bytes32 value) internal returns (bool) {\\n        return _remove(set._inner, value);\\n    }\\n\\n    /**\\n     * @dev Returns true if the value is in the set. O(1).\\n     */\\n    function contains(Bytes32Set storage set, bytes32 value) internal view returns (bool) {\\n        return _contains(set._inner, value);\\n    }\\n\\n    /**\\n     * @dev Returns the number of values in the set. O(1).\\n     */\\n    function length(Bytes32Set storage set) internal view returns (uint256) {\\n        return _length(set._inner);\\n    }\\n\\n   /**\\n    * @dev Returns the value stored at position `index` in the set. O(1).\\n    *\\n    * Note that there are no guarantees on the ordering of values inside the\\n    * array, and it may change when more values are added or removed.\\n    *\\n    * Requirements:\\n    *\\n    * - `index` must be strictly less than {length}.\\n    */\\n    function at(Bytes32Set storage set, uint256 index) internal view returns (bytes32) {\\n        return _at(set._inner, index);\\n    }\\n\\n    // AddressSet\\n\\n    struct AddressSet {\\n        Set _inner;\\n    }\\n\\n    /**\\n     * @dev Add a value to a set. O(1).\\n     *\\n     * Returns true if the value was added to the set, that is if it was not\\n     * already present.\\n     */\\n    function add(AddressSet storage set, address value) internal returns (bool) {\\n        return _add(set._inner, bytes32(uint256(value)));\\n    }\\n\\n    /**\\n     * @dev Removes a value from a set. O(1).\\n     *\\n     * Returns true if the value was removed from the set, that is if it was\\n     * present.\\n     */\\n    function remove(AddressSet storage set, address value) internal returns (bool) {\\n        return _remove(set._inner, bytes32(uint256(value)));\\n    }\\n\\n    /**\\n     * @dev Returns true if the value is in the set. O(1).\\n     */\\n    function contains(AddressSet storage set, address value) internal view returns (bool) {\\n        return _contains(set._inner, bytes32(uint256(value)));\\n    }\\n\\n    /**\\n     * @dev Returns the number of values in the set. O(1).\\n     */\\n    function length(AddressSet storage set) internal view returns (uint256) {\\n        return _length(set._inner);\\n    }\\n\\n   /**\\n    * @dev Returns the value stored at position `index` in the set. O(1).\\n    *\\n    * Note that there are no guarantees on the ordering of values inside the\\n    * array, and it may change when more values are added or removed.\\n    *\\n    * Requirements:\\n    *\\n    * - `index` must be strictly less than {length}.\\n    */\\n    function at(AddressSet storage set, uint256 index) internal view returns (address) {\\n        return address(uint256(_at(set._inner, index)));\\n    }\\n\\n\\n    // UintSet\\n\\n    struct UintSet {\\n        Set _inner;\\n    }\\n\\n    /**\\n     * @dev Add a value to a set. O(1).\\n     *\\n     * Returns true if the value was added to the set, that is if it was not\\n     * already present.\\n     */\\n    function add(UintSet storage set, uint256 value) internal returns (bool) {\\n        return _add(set._inner, bytes32(value));\\n    }\\n\\n    /**\\n     * @dev Removes a value from a set. O(1).\\n     *\\n     * Returns true if the value was removed from the set, that is if it was\\n     * present.\\n     */\\n    function remove(UintSet storage set, uint256 value) internal returns (bool) {\\n        return _remove(set._inner, bytes32(value));\\n    }\\n\\n    /**\\n     * @dev Returns true if the value is in the set. O(1).\\n     */\\n    function contains(UintSet storage set, uint256 value) internal view returns (bool) {\\n        return _contains(set._inner, bytes32(value));\\n    }\\n\\n    /**\\n     * @dev Returns the number of values on the set. O(1).\\n     */\\n    function length(UintSet storage set) internal view returns (uint256) {\\n        return _length(set._inner);\\n    }\\n\\n   /**\\n    * @dev Returns the value stored at position `index` in the set. O(1).\\n    *\\n    * Note that there are no guarantees on the ordering of values inside the\\n    * array, and it may change when more values are added or removed.\\n    *\\n    * Requirements:\\n    *\\n    * - `index` must be strictly less than {length}.\\n    */\\n    function at(UintSet storage set, uint256 index) internal view returns (uint256) {\\n        return uint256(_at(set._inner, index));\\n    }\\n}\\n\"}},\"settings\":{\"remappings\":[],\"optimizer\":{\"enabled\":false,\"runs\":200},\"evmVersion\":\"istanbul\",\"libraries\":{}}}",
  "codeformat": "solidity-standard-json-input",
  "contractname": "/Users/lebedkin/programming/xsigma/truffle-tutorial/SigToken/contracts/SigMasterChef.sol:SigMasterChef",
  "compilerversion": "v0.6.12+commit.27d51765",
  "constructorArguements": "0000000000000000000000006dd0ff86f0fc977fe18df3d5166d222338c76a060000000000000000000000008716d1e0bc3f7f9ec42d784ef95b1f776f067cbd0000000000000000000000008babd6c9c46ec434592d4e9a564fdf8878e3577600000000000000000000000000000000000000000000000000000000007a0753"
}
General exception occured when attempting to insert record
Failed to verify 1 contract(s): SigMasterChef

Hmm too bad. Do you have a repo link as well?

No, my client prefers to keep the repo closed as for now, but I can I share the flattened file will all dependencies, (I haven't figure out whether verify works with flattened file since it looking for artifact file rather than solidity). Does that help?

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol

// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

// File: @openzeppelin/contracts/math/SafeMath.sol

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     *
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     *
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");

        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return mod(a, b, "SafeMath: modulo by zero");
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}

// File: @openzeppelin/contracts/utils/Address.sol

pragma solidity >=0.6.2 <0.8.0;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        // solhint-disable-next-line no-inline-assembly
        assembly { size := extcodesize(account) }
        return size > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
        (bool success, ) = recipient.call{ value: amount }("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain`call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
      return functionCall(target, data, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.call{ value: value }(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.staticcall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                // solhint-disable-next-line no-inline-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

// File: @openzeppelin/contracts/token/ERC20/SafeERC20.sol

pragma solidity >=0.6.0 <0.8.0;

/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using SafeMath for uint256;
    using Address for address;

    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(IERC20 token, address spender, uint256 value) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        // solhint-disable-next-line max-line-length
        require((value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).add(value);
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero");
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.

        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        if (returndata.length > 0) { // Return data is optional
            // solhint-disable-next-line max-line-length
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

// File: @openzeppelin/contracts/utils/EnumerableSet.sol

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Library for managing
 * https://en.wikipedia.org/wiki/Set_(abstract_data_type)[sets] of primitive
 * types.
 *
 * Sets have the following properties:
 *
 * - Elements are added, removed, and checked for existence in constant time
 * (O(1)).
 * - Elements are enumerated in O(n). No guarantees are made on the ordering.
 *
 * ```
 * contract Example {
 *     // Add the library methods
 *     using EnumerableSet for EnumerableSet.AddressSet;
 *
 *     // Declare a set state variable
 *     EnumerableSet.AddressSet private mySet;
 * }
 * ```
 *
 * As of v3.3.0, sets of type `bytes32` (`Bytes32Set`), `address` (`AddressSet`)
 * and `uint256` (`UintSet`) are supported.
 */
library EnumerableSet {
    // To implement this library for multiple types with as little code
    // repetition as possible, we write it in terms of a generic Set type with
    // bytes32 values.
    // The Set implementation uses private functions, and user-facing
    // implementations (such as AddressSet) are just wrappers around the
    // underlying Set.
    // This means that we can only create new EnumerableSets for types that fit
    // in bytes32.

    struct Set {
        // Storage of set values
        bytes32[] _values;

        // Position of the value in the `values` array, plus 1 because index 0
        // means a value is not in the set.
        mapping (bytes32 => uint256) _indexes;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function _add(Set storage set, bytes32 value) private returns (bool) {
        if (!_contains(set, value)) {
            set._values.push(value);
            // The value is stored at length-1, but we add 1 to all indexes
            // and use 0 as a sentinel value
            set._indexes[value] = set._values.length;
            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function _remove(Set storage set, bytes32 value) private returns (bool) {
        // We read and store the value's index to prevent multiple reads from the same storage slot
        uint256 valueIndex = set._indexes[value];

        if (valueIndex != 0) { // Equivalent to contains(set, value)
            // To delete an element from the _values array in O(1), we swap the element to delete with the last one in
            // the array, and then remove the last element (sometimes called as 'swap and pop').
            // This modifies the order of the array, as noted in {at}.

            uint256 toDeleteIndex = valueIndex - 1;
            uint256 lastIndex = set._values.length - 1;

            // When the value to delete is the last one, the swap operation is unnecessary. However, since this occurs
            // so rarely, we still do the swap anyway to avoid the gas cost of adding an 'if' statement.

            bytes32 lastvalue = set._values[lastIndex];

            // Move the last value to the index where the value to delete is
            set._values[toDeleteIndex] = lastvalue;
            // Update the index for the moved value
            set._indexes[lastvalue] = toDeleteIndex + 1; // All indexes are 1-based

            // Delete the slot where the moved value was stored
            set._values.pop();

            // Delete the index for the deleted slot
            delete set._indexes[value];

            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function _contains(Set storage set, bytes32 value) private view returns (bool) {
        return set._indexes[value] != 0;
    }

    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function _length(Set storage set) private view returns (uint256) {
        return set._values.length;
    }

   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function _at(Set storage set, uint256 index) private view returns (bytes32) {
        require(set._values.length > index, "EnumerableSet: index out of bounds");
        return set._values[index];
    }

    // Bytes32Set

    struct Bytes32Set {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(Bytes32Set storage set, bytes32 value) internal returns (bool) {
        return _add(set._inner, value);
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(Bytes32Set storage set, bytes32 value) internal returns (bool) {
        return _remove(set._inner, value);
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(Bytes32Set storage set, bytes32 value) internal view returns (bool) {
        return _contains(set._inner, value);
    }

    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(Bytes32Set storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function at(Bytes32Set storage set, uint256 index) internal view returns (bytes32) {
        return _at(set._inner, index);
    }

    // AddressSet

    struct AddressSet {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(AddressSet storage set, address value) internal returns (bool) {
        return _add(set._inner, bytes32(uint256(value)));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(AddressSet storage set, address value) internal returns (bool) {
        return _remove(set._inner, bytes32(uint256(value)));
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(AddressSet storage set, address value) internal view returns (bool) {
        return _contains(set._inner, bytes32(uint256(value)));
    }

    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(AddressSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function at(AddressSet storage set, uint256 index) internal view returns (address) {
        return address(uint256(_at(set._inner, index)));
    }

    // UintSet

    struct UintSet {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(UintSet storage set, uint256 value) internal returns (bool) {
        return _add(set._inner, bytes32(value));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(UintSet storage set, uint256 value) internal returns (bool) {
        return _remove(set._inner, bytes32(value));
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(UintSet storage set, uint256 value) internal view returns (bool) {
        return _contains(set._inner, bytes32(value));
    }

    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function length(UintSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function at(UintSet storage set, uint256 index) internal view returns (uint256) {
        return uint256(_at(set._inner, index));
    }
}

// File: @openzeppelin/contracts/GSN/Context.sol

pragma solidity >=0.6.0 <0.8.0;

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address payable) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}

// File: @openzeppelin/contracts/access/Ownable.sol

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor () internal {
        address msgSender = _msgSender();
        _owner = msgSender;
        emit OwnershipTransferred(address(0), msgSender);
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(_owner == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

// File: @openzeppelin/contracts/token/ERC20/ERC20.sol

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 * For a generic mechanism see {ERC20PresetMinterPauser}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * We have followed general OpenZeppelin guidelines: functions revert instead
 * of returning `false` on failure. This behavior is nonetheless conventional
 * and does not conflict with the expectations of ERC20 applications.
 *
 * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See {IERC20-approve}.
 */
contract ERC20 is Context, IERC20 {
    using SafeMath for uint256;

    mapping (address => uint256) private _balances;

    mapping (address => mapping (address => uint256)) private _allowances;

    uint256 private _totalSupply;

    string private _name;
    string private _symbol;
    uint8 private _decimals;

    /**
     * @dev Sets the values for {name} and {symbol}, initializes {decimals} with
     * a default value of 18.
     *
     * To select a different value for {decimals}, use {_setupDecimals}.
     *
     * All three of these values are immutable: they can only be set once during
     * construction.
     */
    constructor (string memory name_, string memory symbol_) public {
        _name = name_;
        _symbol = symbol_;
        _decimals = 18;
    }

    /**
     * @dev Returns the name of the token.
     */
    function name() public view returns (string memory) {
        return _name;
    }

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view returns (string memory) {
        return _symbol;
    }

    /**
     * @dev Returns the number of decimals used to get its user representation.
     * For example, if `decimals` equals `2`, a balance of `505` tokens should
     * be displayed to a user as `5,05` (`505 / 10 ** 2`).
     *
     * Tokens usually opt for a value of 18, imitating the relationship between
     * Ether and Wei. This is the value {ERC20} uses, unless {_setupDecimals} is
     * called.
     *
     * NOTE: This information is only used for _display_ purposes: it in
     * no way affects any of the arithmetic of the contract, including
     * {IERC20-balanceOf} and {IERC20-transfer}.
     */
    function decimals() public view returns (uint8) {
        return _decimals;
    }

    /**
     * @dev See {IERC20-totalSupply}.
     */
    function totalSupply() public view override returns (uint256) {
        return _totalSupply;
    }

    /**
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account) public view override returns (uint256) {
        return _balances[account];
    }

    /**
     * @dev See {IERC20-transfer}.
     *
     * Requirements:
     *
     * - `recipient` cannot be the zero address.
     * - the caller must have a balance of at least `amount`.
     */
    function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
        _transfer(_msgSender(), recipient, amount);
        return true;
    }

    /**
     * @dev See {IERC20-allowance}.
     */
    function allowance(address owner, address spender) public view virtual override returns (uint256) {
        return _allowances[owner][spender];
    }

    /**
     * @dev See {IERC20-approve}.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 amount) public virtual override returns (bool) {
        _approve(_msgSender(), spender, amount);
        return true;
    }

    /**
     * @dev See {IERC20-transferFrom}.
     *
     * Emits an {Approval} event indicating the updated allowance. This is not
     * required by the EIP. See the note at the beginning of {ERC20}.
     *
     * Requirements:
     *
     * - `sender` and `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     * - the caller must have allowance for ``sender``'s tokens of at least
     * `amount`.
     */
    function transferFrom(address sender, address recipient, uint256 amount) public virtual override returns (bool) {
        _transfer(sender, recipient, amount);
        _approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance"));
        return true;
    }

    /**
     * @dev Atomically increases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
        return true;
    }

    /**
     * @dev Atomically decreases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `spender` must have allowance for the caller of at least
     * `subtractedValue`.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "ERC20: decreased allowance below zero"));
        return true;
    }

    /**
     * @dev Moves tokens `amount` from `sender` to `recipient`.
     *
     * This is internal function is equivalent to {transfer}, and can be used to
     * e.g. implement automatic token fees, slashing mechanisms, etc.
     *
     * Emits a {Transfer} event.
     *
     * Requirements:
     *
     * - `sender` cannot be the zero address.
     * - `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     */
    function _transfer(address sender, address recipient, uint256 amount) internal virtual {
        require(sender != address(0), "ERC20: transfer from the zero address");
        require(recipient != address(0), "ERC20: transfer to the zero address");

        _beforeTokenTransfer(sender, recipient, amount);

        _balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance");
        _balances[recipient] = _balances[recipient].add(amount);
        emit Transfer(sender, recipient, amount);
    }

    /** @dev Creates `amount` tokens and assigns them to `account`, increasing
     * the total supply.
     *
     * Emits a {Transfer} event with `from` set to the zero address.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     */
    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: mint to the zero address");

        _beforeTokenTransfer(address(0), account, amount);

        _totalSupply = _totalSupply.add(amount);
        _balances[account] = _balances[account].add(amount);
        emit Transfer(address(0), account, amount);
    }

    /**
     * @dev Destroys `amount` tokens from `account`, reducing the
     * total supply.
     *
     * Emits a {Transfer} event with `to` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens.
     */
    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: burn from the zero address");

        _beforeTokenTransfer(account, address(0), amount);

        _balances[account] = _balances[account].sub(amount, "ERC20: burn amount exceeds balance");
        _totalSupply = _totalSupply.sub(amount);
        emit Transfer(account, address(0), amount);
    }

    /**
     * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
     *
     * This internal function is equivalent to `approve`, and can be used to
     * e.g. set automatic allowances for certain subsystems, etc.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     */
    function _approve(address owner, address spender, uint256 amount) internal virtual {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");

        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    /**
     * @dev Sets {decimals} to a value other than the default one of 18.
     *
     * WARNING: This function should only be called from the constructor. Most
     * applications that interact with token contracts will not expect
     * {decimals} to ever change, and may work incorrectly if it does.
     */
    function _setupDecimals(uint8 decimals_) internal {
        _decimals = decimals_;
    }

    /**
     * @dev Hook that is called before any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * will be to transferred to `to`.
     * - when `from` is zero, `amount` tokens will be minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual { }
}

// File: @openzeppelin/contracts/token/ERC20/ERC20Burnable.sol

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Extension of {ERC20} that allows token holders to destroy both their own
 * tokens and those that they have an allowance for, in a way that can be
 * recognized off-chain (via event analysis).
 */
abstract contract ERC20Burnable is Context, ERC20 {
    using SafeMath for uint256;

    /**
     * @dev Destroys `amount` tokens from the caller.
     *
     * See {ERC20-_burn}.
     */
    function burn(uint256 amount) public virtual {
        _burn(_msgSender(), amount);
    }

    /**
     * @dev Destroys `amount` tokens from `account`, deducting from the caller's
     * allowance.
     *
     * See {ERC20-_burn} and {ERC20-allowance}.
     *
     * Requirements:
     *
     * - the caller must have allowance for ``accounts``'s tokens of at least
     * `amount`.
     */
    function burnFrom(address account, uint256 amount) public virtual {
        uint256 decreasedAllowance = allowance(account, _msgSender()).sub(amount, "ERC20: burn amount exceeds allowance");

        _approve(account, _msgSender(), decreasedAllowance);
        _burn(account, amount);
    }
}

// File: contracts/SigToken.sol

pragma solidity 0.6.12;

// SushiToken with Governance.
contract SigToken is ERC20, Ownable, ERC20Burnable {
    using SafeMath for uint256;
    //  Bitcoin-like supply system:
    //      50 tokens per block (however it's Ethereum ~15 seconds block vs Bitcoin 10 minutes)
    //      every 210,000 blocks is halving ~ 36 days 11 hours
    //      32 eras ~  3 years 71 days 16 hours until complete mint
    //      21,000,000 is total supply
    //
    //  i,e. if each block is about 15 seconds on average:
    //      40,320 blocks/week
    //      2,016,000 tokens/week before first halving
    //      10,500,000 total before first halving
    //
    uint256 constant MAX_MAIN_SUPPLY = 21_000_000 * 1e18;

    // the first week mint has x2 bonus     = +2,016,000
    // the second week mint has x1.5 bonus  = +1,008,000
    //
    uint256 constant BONUS_SUPPLY = 3_024_000 * 1e18;

    // so total max supply is 24,024,000 + 24 to init the uniswap pool
    uint256 constant MAX_TOTAL_SUPPLY = MAX_MAIN_SUPPLY + BONUS_SUPPLY;

    // The block number when SIG mining starts.
    uint256 public startBlock;

    uint256 constant DECIMALS_MUL = 1e18;
    uint256 constant BLOCKS_PER_WEEK = 40_320;
    uint256 constant HALVING_BLOCKS = 210_000;
    // uint265 constant INITIAL_BLOCK_REWARD = 50;

    function maxRewardMintAfterBlocks(uint256 t) public pure returns (uint256) {
        // the first week x2 mint
        if (t < BLOCKS_PER_WEEK) {
            return DECIMALS_MUL * 100 * t;
        }
        // second week x1.5 mint
        if (t < BLOCKS_PER_WEEK * 2) {
            return  DECIMALS_MUL * (100 * BLOCKS_PER_WEEK + 75 * (t - BLOCKS_PER_WEEK));
        }
        // after two weeks standard bitcoin issuance model https://en.bitcoin.it/wiki/Controlled_supply
        uint256 totalBonus = DECIMALS_MUL * (BLOCKS_PER_WEEK * 50 + BLOCKS_PER_WEEK * 25);
        assert(totalBonus >= 0);
        // how many halvings so far?
        uint256 era = t / HALVING_BLOCKS;
        assert(0 <= era);
        if (32 <= era) return MAX_TOTAL_SUPPLY;
        // total reward before current era (mul base reward 50)
        // sum : 1 + 1/2 + 1/4 … 1/2^n == 2 - 1/2^n == 1 - 1/1<<n == 1 - 1>>n
        // era reward per block (*1e18 *50)
        if (era == 0) {
            return totalBonus + DECIMALS_MUL* 50 * (t % HALVING_BLOCKS);
        }
        uint256 eraRewardPerBlock = (DECIMALS_MUL >> era);
        //        assert(0 <= eraRewardPerBlock);
        uint256 bcReward = (DECIMALS_MUL + DECIMALS_MUL - (eraRewardPerBlock<<1) ) * 50 * HALVING_BLOCKS;
        //        assert(0 <= bcReward);
        // reward in the last era which isn't over
        uint256 eraReward = eraRewardPerBlock * 50 * (t % HALVING_BLOCKS);
        //        assert(0 <= eraReward);
        uint256 result = totalBonus + bcReward + eraReward;
        assert(0 <= result);
        return result;
    }

    function maxRewardMintAtBlock(uint256 atBlock) public view returns (uint256) {
        if (atBlock < startBlock) return 0;
        uint256 t = atBlock - startBlock;
        return maxRewardMintAfterBlocks(t);
    }

    constructor(
        uint256 _startBlock,
        uint256 _tinyMint
    ) public ERC20("xSigma.fi", "XSIG") {
        startBlock = _startBlock;
        // *option #1*
        // majority of the mining does to LPs via MasterChef,
        // so to prevent potential malicious actions of early LPs on DAO voting
        // 30% supply reserved for the RnD/team goes to the timeVault which has the same unlock/vesting strategy as mint
        // so the team has can vote using their not yet minted (locked/vested) tokens.
        // it means the team would have guaranteed majority at DAO voting for the first: 2 weeks and 12.6 hours
        //      0.3 * 24,024,000 - 0.3* supply(t) > 0.7 * supply(t)
        //      7,207,200 > supply(t)
        //      7,207,200 - 4,032,000[first week] - 3,024,000[second week] = 151,200 on the third week
        //      50/block on the 3rd week, 151,000 / 50 = 3,024 block ~ 12.6 hours
        //
        // _mint(msg.sender, MAX_TOTAL_SUPPLY*10/3);

        // *option #2*
        // DAO would start working from 2nd week
        // dev needs a little of  SIG tokens for uniswap SIG/ETH initialization
        _mint(msg.sender, _tinyMint);
    }

    /// @notice Creates `_amount` token to `_to`. Must only be called by the owner (MasterChef).
    function mint(address _to, uint256 _amount) public onlyOwner {
        _mint(_to, _amount);
        _moveDelegates(address(0), _delegates[_to], _amount);
    }

    // Copied and modified from YAM code:
    // https://github.com/yam-finance/yam-protocol/blob/master/contracts/token/YAMGovernanceStorage.sol
    // https://github.com/yam-finance/yam-protocol/blob/master/contracts/token/YAMGovernance.sol
    // Which is copied and modified from COMPOUND:
    // https://github.com/compound-finance/compound-protocol/blob/master/contracts/Governance/Comp.sol

    /// @dev A record of each accounts delegate
    mapping (address => address) internal _delegates;

    /// @notice A checkpoint for marking number of votes from a given block
    struct Checkpoint {
        uint32 fromBlock;
        uint256 votes;
    }

    /// @notice A record of votes checkpoints for each account, by index
    mapping (address => mapping (uint32 => Checkpoint)) public checkpoints;

    /// @notice The number of checkpoints for each account
    mapping (address => uint32) public numCheckpoints;

    /// @notice The EIP-712 typehash for the contract's domain
    bytes32 public constant DOMAIN_TYPEHASH = keccak256("EIP712Domain(string name,uint256 chainId,address verifyingContract)");

    /// @notice The EIP-712 typehash for the delegation struct used by the contract
    bytes32 public constant DELEGATION_TYPEHASH = keccak256("Delegation(address delegatee,uint256 nonce,uint256 expiry)");

    /// @notice A record of states for signing / validating signatures
    mapping (address => uint) public nonces;

    /// @notice An event thats emitted when an account changes its delegate
    event DelegateChanged(address indexed delegator, address indexed fromDelegate, address indexed toDelegate);

    /// @notice An event thats emitted when a delegate account's vote balance changes
    event DelegateVotesChanged(address indexed delegate, uint previousBalance, uint newBalance);

    /**
     * @notice Delegate votes from `msg.sender` to `delegatee`
     * @param delegator The address to get delegatee for
     */
    function delegates(address delegator) external view returns (address) {
        return _delegates[delegator];
    }

    /**
     * @notice Delegate votes from `msg.sender` to `delegatee`
     * @param delegatee The address to delegate votes to
     */
    function delegate(address delegatee) external {
        return _delegate(msg.sender, delegatee);
    }

    /**
     * @notice Delegates votes from signatory to `delegatee`
     * @param delegatee The address to delegate votes to
     * @param nonce The contract state required to match the signature
     * @param expiry The time at which to expire the signature
     * @param v The recovery byte of the signature
     * @param r Half of the ECDSA signature pair
     * @param s Half of the ECDSA signature pair
     */
    function delegateBySig(address delegatee, uint nonce, uint expiry, uint8 v, bytes32 r, bytes32 s) external {
        bytes32 domainSeparator = keccak256(abi.encode(DOMAIN_TYPEHASH, keccak256(bytes(name())), getChainId(), address(this)));
        bytes32 structHash = keccak256(abi.encode(DELEGATION_TYPEHASH, delegatee, nonce, expiry));
        bytes32 digest = keccak256(abi.encodePacked("\x19\x01", domainSeparator, structHash));
        address signatory = ecrecover(digest, v, r, s);
        require(signatory != address(0), "SIG::delegateBySig: invalid signature");
        require(nonce == nonces[signatory]++, "SIG::delegateBySig: invalid nonce");
        require(now <= expiry, "SIG::delegateBySig: signature expired");
        return _delegate(signatory, delegatee);
    }

    /**
     * @notice Gets the current votes balance for `account`
     * @param account The address to get votes balance
     * @return The number of current votes for `account`
     */
    function getCurrentVotes(address account) external view returns (uint256) {
        uint32 nCheckpoints = numCheckpoints[account];
        return nCheckpoints > 0 ? checkpoints[account][nCheckpoints - 1].votes : 0;
    }

    /**
     * @notice Determine the prior number of votes for an account as of a block number
     * @dev Block number must be a finalized block or else this function will revert to prevent misinformation.
     * @param account The address of the account to check
     * @param blockNumber The block number to get the vote balance at
     * @return The number of votes the account had as of the given block
     */
    function getPriorVotes(address account, uint blockNumber) external view returns (uint256) {
        require(blockNumber < block.number, "SIG::getPriorVotes: not yet determined");

        uint32 nCheckpoints = numCheckpoints[account];
        if (nCheckpoints == 0) {
            return 0;
        }

        // First check most recent balance
        if (checkpoints[account][nCheckpoints - 1].fromBlock <= blockNumber) {
            return checkpoints[account][nCheckpoints - 1].votes;
        }

        // Next check implicit zero balance
        if (checkpoints[account][0].fromBlock > blockNumber) {
            return 0;
        }

        uint32 lower = 0;
        uint32 upper = nCheckpoints - 1;
        while (upper > lower) {
            uint32 center = upper - (upper - lower) / 2; // ceil, avoiding overflow
            Checkpoint memory cp = checkpoints[account][center];
            if (cp.fromBlock == blockNumber) {
                return cp.votes;
            } else if (cp.fromBlock < blockNumber) {
                lower = center;
            } else {
                upper = center - 1;
            }
        }
        return checkpoints[account][lower].votes;
    }

    function _delegate(address delegator, address delegatee) internal {
        address currentDelegate = _delegates[delegator];
        uint256 delegatorBalance = balanceOf(delegator); // balance of underlying SIGs (not scaled);
        _delegates[delegator] = delegatee;

        emit DelegateChanged(delegator, currentDelegate, delegatee);

        _moveDelegates(currentDelegate, delegatee, delegatorBalance);
    }

    function _moveDelegates(address srcRep, address dstRep, uint256 amount) internal {
        if (srcRep != dstRep && amount > 0) {
            if (srcRep != address(0)) {
                // decrease old representative
                uint32 srcRepNum = numCheckpoints[srcRep];
                uint256 srcRepOld = srcRepNum > 0 ? checkpoints[srcRep][srcRepNum - 1].votes : 0;
                uint256 srcRepNew = srcRepOld.sub(amount);
                _writeCheckpoint(srcRep, srcRepNum, srcRepOld, srcRepNew);
            }

            if (dstRep != address(0)) {
                // increase new representative
                uint32 dstRepNum = numCheckpoints[dstRep];
                uint256 dstRepOld = dstRepNum > 0 ? checkpoints[dstRep][dstRepNum - 1].votes : 0;
                uint256 dstRepNew = dstRepOld.add(amount);
                _writeCheckpoint(dstRep, dstRepNum, dstRepOld, dstRepNew);
            }
        }
    }

    function _writeCheckpoint(address delegatee, uint32 nCheckpoints, uint256 oldVotes, uint256 newVotes) internal {
        uint32 blockNumber = safe32(block.number, "SIG::_writeCheckpoint: block number exceeds 32 bits");

        if (nCheckpoints > 0 && checkpoints[delegatee][nCheckpoints - 1].fromBlock == blockNumber) {
            checkpoints[delegatee][nCheckpoints - 1].votes = newVotes;
        } else {
            checkpoints[delegatee][nCheckpoints] = Checkpoint(blockNumber, newVotes);
            numCheckpoints[delegatee] = nCheckpoints + 1;
        }

        emit DelegateVotesChanged(delegatee, oldVotes, newVotes);
    }

    function safe32(uint n, string memory errorMessage) internal pure returns (uint32) {
        require(n < 2**32, errorMessage);
        return uint32(n);
    }

    function getChainId() internal pure returns (uint) {
        uint256 chainId;
        assembly { chainId := chainid() }
        return chainId;
    }
}

// File: contracts/SigMasterChef.sol

/**
 * Fork of MasterChef https://etherscan.io/address/0xc2edad668740f1aa35e4d8f227fb8e17dca888cd#code
*/
// We intentional leave many variables with original sushi name
// so you could save time at diff comparison while verifying the code

pragma solidity 0.6.12;

// former SushiToken

interface IMigratorChef {
    // Perform LP token migration from legacy UniswapV2 to SushiSwap.
    // Take the current LP token address and return the new LP token address.
    // Migrator should have full access to the caller's LP token.
    // Return the new LP token address.
    //
    // XXX Migrator must have allowance access to UniswapV2 LP tokens.
    // SushiSwap must mint EXACTLY the same amount of SushiSwap LP tokens or
    // else something bad will happen. Traditional UniswapV2 does not
    // do that so be careful!
    function migrate(IERC20 token) external returns (IERC20);
}

// MasterChef is the master of Sushi. He can make Sushi and he is a fair guy.
//
// Note that it's ownable and the owner wields tremendous power. The ownership
// will be transferred to a governance smart contract once SUSHI is sufficiently
// distributed and the community can show to govern itself.
//
// Have fun reading it. Hopefully it's bug-free. God bless.
contract SigMasterChef is Ownable {
    using SafeMath for uint256;
    using SafeERC20 for IERC20;

    // Info of each user.
    struct UserInfo {
        uint256 amount;     // How many LP tokens the user has provided.
        uint256 rewardDebt; // Reward debt. See explanation below.
        //
        // We do some fancy math here. Basically, any point in time, the amount of SUSHIs
        // entitled to a user but is pending to be distributed is:
        //
        //   pending reward = (user.amount * pool.accSushiPerShare) - user.rewardDebt
        //
        // Whenever a user deposits or withdraws LP tokens to a pool. Here's what happens:
        //   1. The pool's `accSushiPerShare` (and `lastRewardBlock`) gets updated.
        //   2. User receives the pending reward sent to his/her address.
        //   3. User's `amount` gets updated.
        //   4. User's `rewardDebt` gets updated.
    }

    // Info of each pool.
    struct PoolInfo {
        IERC20 lpToken;           // Address of LP token contract.
        uint256 allocPoint;       // How many allocation points assigned to this pool. SUSHIs to distribute per block.
        uint256 lastRewardBlock;  // Last block number that SUSHIs distribution occurs.
        uint256 accSushiPerShare; // Accumulated SUSHIs per share, times 1e12. See below.
    }

    // The SUSHI TOKEN!
    SigToken public sushi;
    // Dev address // here's it growthFund
    address public devaddr;
    // xSigma's sharedVault of investors
    address public sharedVault;

    // 🐧 all this logic moved to totalReward()
    // // Block number when bonus SUSHI period ends.
    // uint256 public bonusEndBlock; 
    // // SUSHI tokens created per block.
    // uint256 public sushiPerBlock;
    // // Bonus multiplier for early sushi makers.
    // uint256 public constant BONUS_MULTIPLIER = 10; // * moved to supplyFunction

    // The migrator contract. It has a lot of power. Can only be set through governance (owner).
    // IMigratorChef public migrator;

    // Info of each pool.
    PoolInfo[] public poolInfo;
    // Info of each user that stakes LP tokens.
    mapping (uint256 => mapping (address => UserInfo)) public userInfo;
    // Total allocation points. Must be the sum of all allocation points in all pools.
    uint256 public totalAllocPoint = 0;
    // The block number when SUSHI mining starts.
    uint256 public startBlock;
    // reward time factor, the bigger it's the longer it take to distribute reward
    uint256 public rewardTimeFactor = 1;

    event Deposit(address indexed user, uint256 indexed pid, uint256 amount);
    event Withdraw(address indexed user, uint256 indexed pid, uint256 amount);
    event EmergencyWithdraw(address indexed user, uint256 indexed pid, uint256 amount);

    uint256 constant MIN_REWARD_TIME_FACTOR = 1;
    uint256 constant MAX_REWARD_TIME_FACTOR = 40;

    function totalRewardAtBlock(uint256 atBlock) public view returns (uint256) {
        if (atBlock < startBlock) return 0;
        uint256 t = (atBlock - startBlock) / rewardTimeFactor;
        return sushi.maxRewardMintAfterBlocks(t);
    }

    constructor(
        SigToken _sushi,
        address _devaddr,
        address _sharedVault,
    // uint256 _sushiPerBlock,
        uint256 _startBlock
    // uint256 _bonusEndBlock
    ) public {
        sushi = _sushi;
        devaddr = _devaddr;
        sharedVault = _sharedVault;
        // sushiPerBlock = _sushiPerBlock;
        // bonusEndBlock = _bonusEndBlock;
        startBlock = _startBlock;
    }

    function poolLength() external view returns (uint256) {
        return poolInfo.length;
    }

    // beware that chane of this parameter might break the contract
    function changeFactor(uint256 newFactor) public onlyOwner {
        require(MIN_REWARD_TIME_FACTOR <= newFactor && newFactor <= MAX_REWARD_TIME_FACTOR, "Invalid time factor");
        rewardTimeFactor = newFactor;
    }

    // Add a new lp to the pool. Can only be called by the owner.
    // XXX DO NOT add the same LP token more than once. Rewards will be messed up if you do.
    function add(uint256 _allocPoint, IERC20 _lpToken, bool _withUpdate) public onlyOwner {
        if (_withUpdate) {
            massUpdatePools();
        }
        uint256 lastRewardBlock = block.number > startBlock ? block.number : startBlock;
        totalAllocPoint = totalAllocPoint.add(_allocPoint);
        poolInfo.push(PoolInfo({
        lpToken: _lpToken,
        allocPoint: _allocPoint,
        lastRewardBlock: lastRewardBlock,
        accSushiPerShare: 0
        }));
    }

    // Update the given pool's SUSHI allocation point. Can only be called by the owner.
    function set(uint256 _pid, uint256 _allocPoint, bool _withUpdate) public onlyOwner {
        if (_withUpdate) {
            massUpdatePools();
        }
        totalAllocPoint = totalAllocPoint.sub(poolInfo[_pid].allocPoint).add(_allocPoint);
        poolInfo[_pid].allocPoint = _allocPoint;
    }

    //    // Set the migrator contract. Can only be called by the owner.
    //    function setMigrator(IMigratorChef _migrator) public onlyOwner {
    //        migrator = _migrator;
    //    }
    //
    //    // Migrate lp token to another lp contract. Can be called by anyone. We trust that migrator contract is good.
    //    function migrate(uint256 _pid) public {
    //        require(address(migrator) != address(0), "migrate: no migrator");
    //        PoolInfo storage pool = poolInfo[_pid];
    //        IERC20 lpToken = pool.lpToken;
    //        uint256 bal = lpToken.balanceOf(address(this));
    //        lpToken.safeApprove(address(migrator), bal);
    //        IERC20 newLpToken = migrator.migrate(lpToken);
    //        require(bal == newLpToken.balanceOf(address(this)), "migrate: bad");
    //        pool.lpToken = newLpToken;
    //    }

    // Return reward multiplier over the given _from to _to block.
    // function getMultiplier(uint256 _from, uint256 _to) public view returns (uint256) {
    //     if (_to <= bonusEndBlock) {
    //         return _to.sub(_from).mul(BONUS_MULTIPLIER);
    //     } else if (_from >= bonusEndBlock) {
    //         return _to.sub(_from);
    //     } else {
    //         return bonusEndBlock.sub(_from).mul(BONUS_MULTIPLIER).add(
    //             _to.sub(bonusEndBlock)
    //         );
    //     }
    // }
    // how much Sushi was minted from _from block to _to block
    // == sushiPerBlock * getMultiplier(_from, _to);

    // View function to see pending SUSHIs on "frontend".
    function pendingSushi(uint256 _pid, address _user) external view returns (uint256) {
        // better name: currPoolInfo 
        PoolInfo storage pool = poolInfo[_pid];

        // better name: userOfCurrPool
        UserInfo storage user = userInfo[_pid][_user];

        // Accumulated SUSHIs per share, times 1e12.
        uint256 accSushiPerShare = pool.accSushiPerShare;

        // better name: total_staked_LpTokens_of_currPool 
        uint256 lpSupply = pool.lpToken.balanceOf(address(this)); // how many LP_tokens staked in the MasterChef

        // if currPool has any LpToken staked
        if (block.number > pool.lastRewardBlock && lpSupply != 0) {
            // // totalSushi minted / sushiPerBlock on (lastRewardBlock .. block.number]
            // uint256 multiplier = getMultiplier(pool.lastRewardBlock, block.number);
            // 
            // // currPool's reward weight = pool.allocPoint / totalAllocPoint
            // // better name: sushiReward_for_currPool on (lastRewardBlock ... block.number]
            // uint256 sushiReward = multiplier.mul(sushiPerBlock).mul(pool.allocPoint).div(totalAllocPoint);
            //
            // accSushiPerShare = accSushiPerShare.add(sushiReward.mul(1e12).div(lpSupply));

            // 🐧 we use different reward function, so instead the code above:
            uint256 totalSushiReward = totalRewardAtBlock(block.number).sub(totalRewardAtBlock(pool.lastRewardBlock));
            uint256 totalSushiRewardForPool = totalSushiReward.mul(pool.allocPoint).div(totalAllocPoint);
            accSushiPerShare = accSushiPerShare.add(totalSushiRewardForPool.mul(1e12).div(lpSupply));
        }
        // return user.amount.mul(accSushiPerShare).div(1e12).sub(user.rewardDebt);
        // because original sushi contact mints 1 sushi to dev (in addition to 10 for LPs)
        // they implicitly diluted supply for ~9.09% as dev tax
        // to keep math clean, we explicitly we give LPs 60%, growthFund 10%
        // and 30% to xSigma investors and team so and we need to account for that
        uint256 userAmountBeforeTax = user.amount.mul(accSushiPerShare).div(1e12).sub(user.rewardDebt);
        return userAmountBeforeTax.mul(60).div(100);
    }

    // Update reward variables for all pools. Be careful of gas spending!
    function massUpdatePools() public {
        uint256 length = poolInfo.length;
        for (uint256 pid = 0; pid < length; ++pid) {
            updatePool(pid);
        }
    }

    // Update reward variables of the given pool to be up-to-date.
    function updatePool(uint256 _pid) public {
        PoolInfo storage pool = poolInfo[_pid];
        if (block.number <= pool.lastRewardBlock) {
            return;
        }
        uint256 lpSupply = pool.lpToken.balanceOf(address(this));
        if (lpSupply == 0) {
            pool.lastRewardBlock = block.number;
            return;
        }

        // // multiplier * sushiPerBlock = total sushi minted (pool.lastRewardBlock, block.number)
        // uint256 multiplier = getMultiplier(pool.lastRewardBlock, block.number);

        // // poolWeight * total_minted
        // // better name: sushiReward_for_currPool on (pool.lastRewardBlock, block.number)
        // uint256 sushiReward = multiplier.mul(sushiPerBlock).mul(pool.allocPoint).div(totalAllocPoint);

        // 🐧 we use different reward function, so instead the code above:
        uint256 totalSushiReward = totalRewardAtBlock(block.number) - totalRewardAtBlock(pool.lastRewardBlock);
        uint256 totalSushiRewardForPool = totalSushiReward.mul(pool.allocPoint).div(totalAllocPoint);

        // 60% for Lps
        sushi.mint(address(this), totalSushiRewardForPool.mul(60).div(100));
        // 10% for growthFund
        sushi.mint(devaddr, totalSushiRewardForPool.div(10));
        // 30% are minted/unlock directly from reward token
        sushi.mint(address(sharedVault), totalSushiRewardForPool.mul(30).div(100));

        pool.accSushiPerShare = pool.accSushiPerShare.add(totalSushiRewardForPool.mul(1e12).div(lpSupply));
        // 
        pool.lastRewardBlock = block.number;
    }

    // Deposit LP tokens to MasterChef for SUSHI allocation.
    function deposit(uint256 _pid, uint256 _amount) public {
        PoolInfo storage pool = poolInfo[_pid];
        UserInfo storage user = userInfo[_pid][msg.sender];
        updatePool(_pid);
        if (user.amount > 0) {
            uint256 pending = user.amount.mul(pool.accSushiPerShare).div(1e12).sub(user.rewardDebt);
            if(pending > 0) {
                safeSushiTransfer(msg.sender, pending);
            }
        }
        if(_amount > 0) {
            pool.lpToken.safeTransferFrom(address(msg.sender), address(this), _amount);
            user.amount = user.amount.add(_amount);
        }
        // I could do this instead: user.rewardDebt += pending
        user.rewardDebt = user.amount.mul(pool.accSushiPerShare).div(1e12);
        emit Deposit(msg.sender, _pid, _amount);
    }

    // Withdraw LP tokens from MasterChef.
    function withdraw(uint256 _pid, uint256 _amount) public {
        PoolInfo storage pool = poolInfo[_pid];
        UserInfo storage user = userInfo[_pid][msg.sender];
        require(user.amount >= _amount, "withdraw: not good");
        updatePool(_pid);
        uint256 pending = user.amount.mul(pool.accSushiPerShare).div(1e12).sub(user.rewardDebt);
        if(pending > 0) {
            safeSushiTransfer(msg.sender, pending);
        }
        if(_amount > 0) {
            user.amount = user.amount.sub(_amount);
            pool.lpToken.safeTransfer(address(msg.sender), _amount);
        }
        user.rewardDebt = user.amount.mul(pool.accSushiPerShare).div(1e12);
        emit Withdraw(msg.sender, _pid, _amount);
    }

    // Withdraw without caring about rewards. EMERGENCY ONLY.
    function emergencyWithdraw(uint256 _pid) public {
        PoolInfo storage pool = poolInfo[_pid];
        UserInfo storage user = userInfo[_pid][msg.sender];
        uint256 amount = user.amount;
        user.amount = 0;
        user.rewardDebt = 0;
        pool.lpToken.safeTransfer(address(msg.sender), amount);
        emit EmergencyWithdraw(msg.sender, _pid, amount);
    }

    // Safe sushi transfer function, just in case if rounding error causes pool to not have enough SUSHIs.
    function safeSushiTransfer(address _to, uint256 _amount) internal {
        uint256 sushiBal = sushi.balanceOf(address(this));
        if (_amount > sushiBal) {
            sushi.transfer(_to, sushiBal);
        } else {
            sushi.transfer(_to, _amount);
        }
    }

    // Update dev address by the previous dev.
    function dev(address _devaddr) public {
        require(msg.sender == devaddr, "dev: wut?");
        devaddr = _devaddr;
    }
}

rkalis / truffle-plugin-verify

Fix "ParserError: Multiple SPDX license identifiers found in source file" #52