docs: 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)