关闭Kivy中的弹出窗口

from kivy.app import App
from kivy.uix.button import Button
from kivy.uix.popup import Popup
from kivy.uix.label import Label

class MyPopup(Popup):
    pass

class MyApp(App):
    def build(self):
        button = Button(text='Open Popup', on_release=self.open_popup)
        return button

    def open_popup(self, instance):
        popup = MyPopup(title='My Popup', content=Label(text='Hello, World!'))
        popup.open()

        # 关闭弹出窗口
        popup.dismiss()

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