How to keep effects of image filters going for some seconds?

[Ren Wenshan]

Hello, every pythoner.

Firstly, I want to mention that English is my second language, so
maybe there are some sentences which makes you confused, sorry.

I have been learning Panda3D, an open source 3D engine, these days.
Now, I'm trying to write a small game for fun and practice. However,
I've ran into a problem.

I want to make some speical effects and there is my code:

def ventose(self):

    global potato_HP

    if potato_HP[0] == 1 and potato_HP[1] == 0:
    if random() > .30:
        self.filters.setCartoonInk(separation = 0.8)
        self.robotVincent.resetHead.start()
        self.decreaseVincentHP()
            Wait(3)
            self.fliters.delCartoonInk()

However, it doesn't work, the CartoonInk effect will never been shown
in my game and I don't want my game to wait three seconds, what I need
is to keep the effect for a period of time while the game run as well.

Besides that, I also want to show a counting back like "3", then "2",
then "1", finally "Go".

As a beginner, I don't know how to do them properly.

Please give me some directions, thank you.


-----------------------------
Vincent Ren