code: def watch(self):
          
          yield pubsub.subscribe()
          while 1:
              messages = yield pubsub.fetch()
              print messages
              try:
                  yield self.messages.put_nowait(messages)
              except:
                  print 'Client %s is dead.' % self
                  self.dead = True
                  break
docs: This is a coroutine that runs permanently for each participant to the
          chat. If the participant has more than 10 unpulled messages this
          coroutine will die.
  
          `pubsub` is a queue that hosts the messages from all the
          participants.
            * subscribe registers this coro to the queue
            * fetch pulls the recent messages from the queue or waits if there
          are no new ones.
  
          self.messages is another queue for the frontend comet client (the
          pull action from the ChatController will pop messages from this queue)