python kivy如何将我的文本文件保存到内部存储器(文件管理器)

from kivy.app import App
from kivy.uix.button import Button
from kivy.uix.filechooser import FileChooserListView
from kivy.uix.boxlayout import BoxLayout

class MyApp(App):
    def build(self):
        layout = BoxLayout(orientation='vertical')
        file_chooser = FileChooserListView()
        save_button = Button(text='Save', on_release=self.save_file)
        layout.add_widget(file_chooser)
        layout.add_widget(save_button)
        return layout

    def save_file(self, instance):
        file_path = instance.parent.children[0].selection[0]
        with open(file_path, 'w') as file:
            file.write('Hello, World!')

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