def test_gaierror(self):
        """
        L{error.getConnectError} converts to a L{error.UnknownHostError} given
        a C{socket.gaierror} instance.
        """
        result = error.getConnectError(socket.gaierror(12, "hello"))
        self.assertCorrectException(12, "hello", result, error.UnknownHostError)

        L{error.getConnectError} converts to a L{error.UnknownHostError} given
        a C{socket.gaierror} instance.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_error.py