interface TokenRecipient {

    /// 授权合约使用代币
    function receiveApproval(address _from, uint256 _value, address _tokenContract, bytes calldata _extraData) external;
}
/// 代币接口
function receiveApproval(address _from, uint256 _value, address _tokenContract, bytes calldata _extraData) external;

/// 授权合约使用代币