def connectionLost(self, reason):
        """
        The connection to the server has been lost.

        If we have a full response from the server, then parse it and fired a
        Deferred with the return value or C{Fault} that the server gave us.
        """
        http.HTTPClient.connectionLost(self, reason)
        if self._response is not None:
            response, self._response = self._response, None
            self.factory.parseResponse(response)

        The connection to the server has been lost.

        If we have a full response from the server, then parse it and fired a
        Deferred with the return value or C{Fault} that the server gave us.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/xmlrpc.py