code: def clone(self, screen, scene):
          
          # Only clone the object if the function is safe to do so.
          if self._on_close is None or isfunction(self._on_close):
              scene.add_effect(PopUpDialog(screen, self._text, self._buttons, self._on_close))
docs: Create a clone of this Dialog into a new Screen.
  
          :param screen: The new Screen object to clone into.
          :param scene: The new Scene object to clone into.