    def __init__(self, screen, bg=0, **kwargs):
        """
        :param screen: The Screen being used for the Scene.
        :param bg: Optional background colour to use for the wipe.

        Also see the common keyword arguments in :py:obj:`.Effect`.
        """
        super().__init__(screen, **kwargs)
        self._bg = bg
        self._y = None
:param screen: The Screen being used for the Scene.
:param bg: Optional background colour to use for the wipe.

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