docs: def connect(self):
          """
          Create internal connection to AMQP service.
          """
          logging.info("Connecting to {} with user {}.".format(self.host, self.username))
          credentials = pika.PlainCredentials(self.username, self.password)
          connection_params = pika.ConnectionParameters(host=self.host,
                                                        credentials=credentials,
                                                        heartbeat_interval=self.heartbeat_interval)
          self.connection = pika.BlockingConnection(connection_params)