Optimize code for gas saving

[coveralls]

Pull Request Test Coverage Report for Build 1186848708

• 0 of 4 (0.0%) changed or added relevant lines in 3 files are covered.
• 2 unchanged lines in 1 file lost coverage.
• Overall coverage remained the same at 0.0%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
contracts/SocialTokenV0.sol	0	1	0.0%
contracts/base/BaseNFT1155.sol	0	1	0.0%
contracts/base/BaseNFT721.sol	0	2	0.0%
<!--	Total:	0	4	0.0%	-->

Files with Coverage Reduction	New Missed Lines	%
contracts/base/BaseNFT721.sol	2	0%
<!--	Total:	2		-->

Totals
Change from base Build 1186837619:	0.0%
Covered Lines:	0
Relevant Lines:	723

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💛 - Coveralls