Run example broker.py in the background Run example simple_send.py to send messages everything is OK Run example simple_recv.py to receive messages receiver ends without error broker ends with exception: Traceback (most recent call last): File "./broker.py" , line 123, in <module> Container(Broker(opts.address)).run() File "/usr/lib/python2.6/site-packages/proton/_reactor.py" , line 180, in run while self.process(): pass File "/usr/lib/python2.6/site-packages/proton/_reactor.py" , line 206, in process self._check_errors() File "/usr/lib/python2.6/site-packages/proton/_reactor.py" , line 202, in _check_errors _compat.raise_(exc, value, tb) File "/usr/lib/python2.6/site-packages/proton/_reactor_impl.py" , line 133, in dispatch ev.dispatch(self.handler) File "/usr/lib/python2.6/site-packages/proton/_events.py" , line 254, in dispatch self.dispatch(h, type) File "/usr/lib/python2.6/site-packages/proton/_events.py" , line 251, in dispatch result = _dispatch(handler, type.method, self) File "/usr/lib/python2.6/site-packages/proton/_events.py" , line 113, in _dispatch return m(*args) File "/usr/lib/python2.6/site-packages/proton/_handlers.py" , line 270, in on_link_remote_close self.on_link_closing(event) File "/usr/lib/python2.6/site-packages/proton/_handlers.py" , line 398, in on_link_closing _dispatch(self.delegate, 'on_link_closing' , event) File "/usr/lib/python2.6/site-packages/proton/_events.py" , line 113, in _dispatch return m(*args) File "./broker.py" , line 96, in on_link_closing self._unsubscribe(event.link) File "./broker.py" , line 91, in _unsubscribe if link.source.address in self.queues and self.queues[link.source.address].unsubscribe(link): File "./broker.py" , line 38, in unsubscribe return len(self.consumers) == 0 and (self.dynamic or self.queue.count == 0) AttributeError: 'collections.deque' object has no attribute 'count'