Open a new channel with RabbitMQ.

        When RabbitMQ responds that the channel is open, the on_channel_open
        callback will be invoked by pika.

def open_channel(self):
        """Open a new channel with RabbitMQ.

        When RabbitMQ responds that the channel is open, the on_channel_open
        callback will be invoked by pika.
        """
        logger.debug('Creating new channel')
        self._connection.channel(on_open_callback=self.on_channel_open)