code: def unsubscribe(self, subscription, drop_callback_reference=False, **kwargs):
          
          if subscription not in self.__subscriptions:
              raise workflows.Error("Attempting to unsubscribe unknown subscription")
          if self.__subscriptions[subscription]["unsubscribed"]:
              raise workflows.Error(
                  "Attempting to unsubscribe already unsubscribed subscription"
              )
          self._unsubscribe(subscription, **kwargs)
          self.__subscriptions[subscription]["unsubscribed"] = True
          if drop_callback_reference:
              self.drop_callback_reference(subscription)
docs: Stop listening to a queue or a broadcast
          :param subscription: Subscription ID to cancel
          :param drop_callback_reference: Drop the reference to the registered
                                          callback function immediately. This
                                          means any buffered messages still in
                                          flight will not arrive at the intended
                                          destination and cause exceptions to be
                                          raised instead.
          :param **kwargs: Further parameters for the transport layer.