def blink(self):

# Animation that changes the blink size and opacity

anim = Animation(outer_opacity=0, blink_size=50)

# when yhe animation completes, reset the animation, then repeat

anim.bind(on_complete=self.reset)

anim.start(self)

def reset(self, *args):

self.outer_opacity = 1

self.blink_size = self.default_blink_size

self.blink()