Python Kivy:如何将实例变量传递给另一个窗口(类)？

class MainWindow(Screen):
    data = StringProperty()

class MainWindow(Screen):
    data = StringProperty()

    def set_data(self, value):
        self.data = value

class MainWindow(Screen):
    data = StringProperty()

    def set_data(self, value):
        self.data = value

# 在Kivy的布局文件中使用Button组件，并将其绑定到set_data方法
Button:
    text: "传递数据"
    on_release: app.root.set_data("Hello World")

class AnotherWindow(Screen):
    def get_data(self):
        main_window = App.get_running_app().root
        data_value = main_window.data
        print(data_value)