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));
	}

	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.

		// A Solidity high level call has three parts:
		//  1. The target address is checked to verify it contains contract code
		//  2. The call itself is made, and success asserted
		//  3. The return value is decoded, which in turn checks the size of the returned data.
		// solhint-disable-next-line max-line-length
		require(address(token).isContract(), "SafeERC20: call to non-contract");

		// solhint-disable-next-line avoid-low-level-calls
		(bool success, bytes memory returndata) = address(token).call(data);
		require(success, "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");
		}
	}
}
/**
 * @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 ERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
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.

		// A Solidity high level call has three parts:
		//  1. The target address is checked to verify it contains contract code
		//  2. The call itself is made, and success asserted
		//  3. The return value is decoded, which in turn checks the size of the returned data.
		// solhint-disable-next-line max-line-length
		require(address(token).isContract(), "SafeERC20: call to non-contract");

		// solhint-disable-next-line avoid-low-level-calls
		(bool success, bytes memory returndata) = address(token).call(data);
		require(success, "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");
		}
	}
/**
 	 * @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).
 	 */