def cmd_CLIENT_ERROR(self, errText):
        """
        An invalid input as been sent.
        """
        errText = repr(errText)
        log.err("Invalid input: " + errText)
        cmd = self._current.popleft()
        cmd.fail(ClientError(errText))

        An invalid input as been sent.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/protocols/memcache.py