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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 add_on_channel_close_callback(self):
 """ Tell pika to call the on_channel_closed method if RabbitMQ unexpectedly closes the channel. """

        self._logger.info('Adding channel close callback')
        self._channel.add_on_close_callback(self.on_channel_closed)