def finish():
        """
        Callback called when the request is closing.

        @return: If necessary, the pending data accumulated from previous
            C{encode} calls.
        @rtype: L{str}
        """

        Callback called when the request is closing.

        @return: If necessary, the pending data accumulated from previous
            C{encode} calls.
        @rtype: L{str}
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/iweb.py