'Do the initialization of incoming animation here.
Override to set your custom animation.'

def open(self):

    def on_complete(*l):
        self.dispatch('on_activate')
    self.opacity = 0
    super(AnimatedPopup, self).open()
    anim = Factory.Animation(opacity=1, d=self.anim_duration)
    anim.bind(on_complete=on_complete)
    anim.start(self)
