code: def register_callback_subscribed(self, callback):
          
          return self.__client.register_callback_created(partial(self.__callback_subscribed_filter, callback),
                                                         serialised=False)
docs: Register a callback for new subscription. This gets called whenever one of *your* things subscribes to something
          else.
  
          `Note` it is not called when whenever something else subscribes to your thing.
  
          The payload passed to your callback is either a
          [RemoteControl](RemotePoint.m.html#IoticAgent.IOT.RemotePoint.RemoteControl) or
          [RemoteFeed](RemotePoint.m.html#IoticAgent.IOT.RemotePoint.RemoteFeed) instance.