Lesson 7: unknown function or type 'gasleft'

[DorianDaSilva]

Hi,

the function below is throwing an "unknow function or type" error when calling gasleft() and (bool success) is not being read.

    function callBackWithRandomness(
        bytes32 requestId,
        uint256 randomness,
        address consumerContract
    ) public {
        VRFConsumerBase v;
        bytes memory resp = abi.encodeWithSelector(v.rawFulfillRandomness.selector, requestId, randomness);
        uint256 b = 206000;
        require(gasleft() >= b, "not enough gas for consumer");
        (bool success,) = consumerContract.call(resp);
    }

thank you