def unplug(self):
        '''Remove the actor's methods from the callback registry.'''
        if not self.__plugged:
            return
        members = set([method for _, method
                      in inspect.getmembers(self, predicate=inspect.ismethod)])
        for message in global_callbacks:
            global_callbacks[message] -= members
        self.__plugged = False
Remove the actor's methods from the callback registry.