在Kivy (Python)中跨屏幕更新标签-使用ScreenManager在.kv和.py文件之间缺乏交互的问题

ScreenManager:
    MenuScreen:
    InfoScreen:

<MenuScreen>:
    name: 'menu'
    BoxLayout:
        orientation: 'vertical'
        Label:
            id: label1
            text: 'Menu Screen'
        Button:
            text: 'Go to Info Screen'
            on_release: app.root.current = 'info'

<InfoScreen>:
    name: 'info'
    BoxLayout:
        orientation: 'vertical'
        Label:
            id: label2
            text: 'Info Screen'
        Button:
            text: 'Go back to Menu Screen'
            on_release: app.root.current = 'menu'

from kivy.app import App
from kivy.uix.screenmanager import ScreenManager, Screen

class MenuScreen(Screen):
    pass

class InfoScreen(Screen):
    pass

class MyApp(App):
    def build(self):
        sm = ScreenManager()
        sm.add_widget(MenuScreen(name='menu'))
        sm.add_widget(InfoScreen(name='info'))
        return sm

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

self.root.ids.label1.text = 'New Text'

self.root.ids.label2.text = 'New Text'