def ack(self):
        """Acknowledge this message as being processed.,
        This will remove the message from the queue.

        :raises MessageStateError: If the message has already been
            acknowledged/requeued/rejected.

        """
        if self.acknowledged:
            raise self.MessageStateError(
                self._state % "Message already acknowledged with state: %s")
        self.backend.ack(self._frame)
        self._state = "ACK"
dataset/ETHPy150Open ask/carrot/carrot/backends/pystomp.py/Message.ack/swapped operands of `%`