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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def send_ack(self):
 """Send an ack message"""


        if self.last_ack == self.proto.max_id:
            return
        LOGGER.debug("ack (%d)", self.proto.max_id)
        self.last_ack = self.proto.max_id
        self.send_message(f"4{to_json([self.proto.max_id])}")