def assertClientTransportState(self, client, immediateClose):
        """
        Make an assertion about the connectedness of the given protocol's
        transport.  Override this to implement either a check for the
        connection still being open or having been closed as appropriate.

        @param client: The client whose state is being checked.

        @param immediateClose: Boolean indicating whether the connection was
            closed immediately or not.
        """
        raise NotImplementedError(
            "%r did not implement assertClientTransportState" % (
                self.__class__.__name__,))

        Make an assertion about the connectedness of the given protocol's
        transport.  Override this to implement either a check for the
        connection still being open or having been closed as appropriate.

        @param client: The client whose state is being checked.

        @param immediateClose: Boolean indicating whether the connection was
            closed immediately or not.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/test/test_endpoints.py