def readlines(self, size=None):
        """
        Pass through to the underlying C{readlines}.

        This is called in a WSGI application thread, not the I/O thread.
        """
        # Avoid passing None because cStringIO and file don't like it.
        if size is None:
            return self._wrapped.readlines()
        return self._wrapped.readlines(size)

        Pass through to the underlying C{readlines}.

        This is called in a WSGI application thread, not the I/O thread.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/wsgi.py