code: def after(self, callback: Union[Callable, str]) -> "Control":
          
          if isinstance(callback, Control):
              callback = callback._after
          self._after = callback
          return self
docs: Register a control method that reacts after the trigger method is called.
  
          Parameters:
              callback:
                  The control method. If given as a callable, then that function will be
                  used as the callback. If given as a string, then the control will look
                  up a method with that name when reacting (useful when subclassing).