    def __init__(self, screen, renderer, y, x=None, colour=7, attr=0, bg=0,
                 clear=False, transparent=True, speed=4, **kwargs):
        """
        :param screen: The Screen being used for the Scene.
        :param renderer: The renderer to be printed.
        :param x: The column (x coordinate) for the start of the text.
            If not specified, defaults to centring the text on screen.
        :param y: The line (y coordinate) for the start of the text.
        :param colour: The foreground colour to use for the text.
        :param attr: The colour attribute to use for the text.
        :param bg: The background colour to use for the text.
        :param clear: Whether to clear the text before stopping.
        :param transparent: Whether to print spaces (and so be able to overlay other Effects).
            If False, this will redraw all characters and so replace any Effect underneath it.
        :param speed: The refresh rate in frames between updates.

        Note that a speed of 1 will force the Screen to redraw the Effect every frame update, while a value
        of 0 will redraw on demand - i.e. will redraw every time that an update is required by another Effect.

        Also see the common keyword arguments in :py:obj:`.Effect`.
        """
        super().__init__(screen, **kwargs)
        self._renderer = renderer
        self._transparent = transparent
        self._y = y
        self._x = ((self._screen.width - renderer.max_width) // 2 if x is None
                   else x)
        self._colour = colour
        self._attr = attr
        self._bg = bg
        self._clear = clear
        self._speed = speed
        self._frame_no = 0
:param screen: The Screen being used for the Scene.
:param renderer: The renderer to be printed.
:param x: The column (x coordinate) for the start of the text.
If not specified, defaults to centring the text on screen.
:param y: The line (y coordinate) for the start of the text.
:param colour: The foreground colour to use for the text.
:param attr: The colour attribute to use for the text.
:param bg: The background colour to use for the text.
:param clear: Whether to clear the text before stopping.
:param transparent: Whether to print spaces (and so be able to overlay other Effects).
If False, this will redraw all characters and so replace any Effect underneath it.
:param speed: The refresh rate in frames between updates.

Note that a speed of 1 will force the Screen to redraw the Effect every frame update, while a value
of 0 will redraw on demand - i.e. will redraw every time that an update is required by another Effect.

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