def METHOD_NAME(self,e):
    btn = e.get_target()
    if not self.anim_timeline:
        self.anim_timeline_create()
    reverse = btn.has_state(lv.STATE.CHECKED)
    lv.anim_timeline_set_reverse(self.anim_timeline,reverse)
    lv.anim_timeline_start(self.anim_timeline)