Add method of director to be called on screen touch

        self._ensure_minimum_presentation_time()

        self.nothing_requested()

    def screen_touched(self) -> None:

        # TODO Extend this to take x: int, y: int parameters

        # TODO Maybe also add a screen_touch_released method etc.

        if self._next_scene_on_card_placed is not self.play.Balance:

            self.balance_requested()    

    def _ensure_minimum_presentation_time(self) -> None:

        """

        Ensure that the presentation of a "card placed" scene lasts for at least a certain time.