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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 setup_exchange(self):
 """Declare the exchange When completed, the on_exchange_declareok method will be invoked by pika. """

        logger.debug('Declaring exchange %s', self._exchange)
        self._channel.exchange_declare(self.on_exchange_declareok,
                                       self._exchange,
                                       self._exchange_type,
                                       durable=True)