fail to map `cmmand + option + arrow` to `option + arrow`

[XixianLiang]

In chrome. cmmand + option + arrow can navigate between tabs，and I want to map it to option + arrow. The following config is what I wrote for this function, but it doesn't work. What's wrong with this config?

{
    "description": "Map Command + Option + Arrow to Option + Arrow",
    "manipulators": [
        {
            "from": {
                "key_code": "left_arrow",
                "modifiers": {
                    "mandatory": [
                        "command",
                        "option"
                    ]
                }
            },
            "to": [
                {
                    "key_code": "left_arrow",
                    "modifiers": [
                        "option"
                    ]
                }
            ],
            "type": "basic"
        },
        {
            "from": {
                "key_code": "right_arrow",
                "modifiers": {
                    "mandatory": [
                        "command",
                        "option"
                    ]
                }
            },
            "to": [
                {
                    "key_code": "right_arrow",
                    "modifiers": [
                        "option"
                    ]
                }
            ],
            "type": "basic"
        }
    ]
}

[tekezo]

The rules change command+option+arrows. If you want to change option+arrows to switch tabs, you should swap “from” and “to” in the JSON.

[XixianLiang]

The rules change command+option+arrows. If you want to change option+arrows to switch tabs, you should swap “from” and “to” in the JSON.

I'm confused about the grammar. It always throws "json must be object".

Here's the config.

{
    "description": "Map Command + Option + Arrow to Option + Arrow",
    "manipulators": [
        {
            "to": {
                "key_code": "left_arrow",
                "modifiers": {
                    "mandatory": [
                        "command",
                        "option"
                    ]
                }
            },
            "from": 
                {
                    "key_code": "left_arrow",
                    "modifiers": [
                        "option"
                    ]
                }
            ,
            "type": "basic"
        },
        {
            "to": {
                "key_code": "right_arrow",
                "modifiers": {
                    "mandatory": [
                        "command",
                        "option"
                    ]
                }
            },
            "from": 
                {
                    "key_code": "right_arrow",
                    "modifiers": [
                        "option"
                    ]
                }
            ,
            "type": "basic"
        }
    ]
}

[tekezo]

Please try this json.

{
    "description": "Map Command + Option + Arrow to Option + Arrow",
    "manipulators": [
        {
            "from": {
                "key_code": "left_arrow",
                "modifiers": {
                    "mandatory": [
                        "option"
                    ]
                }
            },
            "to": [
                {
                    "key_code": "left_arrow",
                    "modifiers": [
                        "command",
                        "option"
                    ]
                }
            ],
            "type": "basic"
        },
        {
            "from": {
                "key_code": "right_arrow",
                "modifiers": {
                    "mandatory": [
                        "option"
                    ]
                }
            },
            "to": [
                {
                    "key_code": "right_arrow",
                    "modifiers": [
                        "command",
                        "option"
                    ]
                }
            ],
            "type": "basic"
        }
    ]
}

[XixianLiang]

Please try this json.

It works. Thank you very much. And what's wrong with my config?