def _connectionLost_WAITING(self, reason):
        """
        Disconnect the response parser so that it can propagate the event as
        necessary (for example, to call an application protocol's
        C{connectionLost} method, or to fail a request L{Deferred}) and move
        to the C{'CONNECTION_LOST'} state.
        """
        self._disconnectParser(reason)
        self._state = 'CONNECTION_LOST'

        Disconnect the response parser so that it can propagate the event as
        necessary (for example, to call an application protocol's
        C{connectionLost} method, or to fail a request L{Deferred}) and move
        to the C{'CONNECTION_LOST'} state.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/_newclient.py