def _deliverBody_FINISHED(self, protocol):
        """
        It is invalid to attempt to deliver data to a protocol after the
        response body has been delivered to another protocol.
        """
        raise RuntimeError(
            u"Response already finished, cannot deliverBody now.")

        It is invalid to attempt to deliver data to a protocol after the
        response body has been delivered to another protocol.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/_newclient.py