Python 使用KIVY卡在加载窗口中

我正在使用Python和Kivy学习POS教程，我被这个错误卡住了，这个错误似乎消失了，并且不断地出现。我有一个main.py文件，试图在其中加载一个抛出属性错误的window admin.py

  File "C:/Users/John/PycharmProjects/FirstKivyApplication/main.py", line 3, in <module>
     from Admin.admin import AdminWindow
   File "C:\Users\John\PycharmProjects\FirstKivyApplication\Admin\admin.py", line 22, in <module>
     Builder.load_file('Admin/admin.kv')
   File "C:\Users\John\PycharmProjects\FirstKivyApplication\lib\site-packages\kivy\lang\builder.py", line 301, in load_file
     return self.load_string(data, **kwargs)
   File "C:\Users\John\PycharmProjects\FirstKivyApplication\lib\site-packages\kivy\lang\builder.py", line 399, in load_string
     widget = Factory.get(parser.root.name)(__no_builder=True)
   File "C:\Users\John\PycharmProjects\FirstKivyApplication\lib\site-packages\kivy\factory.py", line 130, in __getattr__
     raise AttributeError
 AttributeError

管理员

from kivy.uix.modalview import ModalView
from kivy.lang import Builder

Builder.load_file('Admin/admin.kv')

class Notify(ModalView):
    def __init__(self, **kwargs):
        super().__init__(**kwargs)

        self.size_hint = (.3, .3)


class AdminWindow(BoxLayout):
    def __init__(self, **kwargs):
        super().__init__(**kwargs)


    def logout(self):
        self.parent.parent.current = 'scrn_si'

class AdminApp(App):
    def build(self):
        return AdminWindow()


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

这是我的项目结构：

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我在相关文件中忘记了下面的这句话

#: import Window kivy.core.window.Window

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我忘记了相关文件中下面的陈述

#: import Window kivy.core.window.Window