如何在每次调用时重新启动kivy动画？

from kivy.app import App
from kivy.uix.widget import Widget
from kivy.animation import Animation

class MyWidget(Widget):
    def __init__(self, **kwargs):
        super(MyWidget, self).__init__(**kwargs)
        self.animation = Animation(pos=(100, 100), duration=1)  # 创建动画对象

    def start_animation(self):
        self.animation.start(self)  # 启动动画

    def stop_animation(self):
        self.animation.stop(self)  # 停止动画

class MyApp(App):
    def build(self):
        widget = MyWidget()
        widget.start_animation()  # 在应用程序启动时开始动画
        return widget

if __name__ == '__main__':
    MyApp().run()