Collision notifications

[CarlosRamos]

I'm using the collision notification mechanism in Vizard, and I want to detect if one object collides with another and apply a force if that happens. But the problem is I can't identify the object. For example, let's say I have an object called "ball", and a object called "racket" already defined and loaded previously on the script, and with the viz.COLLIDE_NOTIFY flag enabled. Then I define the collide notification function:

def collideNot(e):
     if e.obj1 == ball or e.obj2 == ball:
         print "collision"
     else:
         print "no collision"

It always shows "no collision". Am I doing something wrong? Thanks in advance.