    def __init__(self, screen, rate, **kwargs):
        """
        :param screen: The Screen being used for the Scene.
        :param rate: How many frames to wait between scrolling the screen.

        Also see the common keyword arguments in :py:obj:`.Effect`.
        """
        super().__init__(screen, **kwargs)
        self._rate = rate
        self._last_frame = None
:param screen: The Screen being used for the Scene.
:param rate: How many frames to wait between scrolling the screen.

Also see the common keyword arguments in :py:obj:`.Effect`.
asciimatics/effects.py