code: def trigger_staged_hook(self, name, *args, **kwargs):
          
          self.trigger_hook("pre_" + name, *args, **kwargs)
          self.trigger_hook("on_" + name, *args, **kwargs)
          self.trigger_hook("post_" + name, *args, **kwargs)
docs: Calls a three-staged hook:
          
          1. ``"pre_"+name``
          2. ``"_on_"+name``
          3. ``"post_"+name``