[Python] line 987, in add_widget raise ScreenManagerException(...

I keep getting this error: line 987, in add_widget raise ScreenManagerException( kivy.uix.screenmanager.ScreenManagerException: ScreenManager accepts only Screen widget.

I've tried everything. Posted all my code to Grok and that found no issues. I've cleared cache, uninstalled and reinstalled kivy and dependencies, watched videos on youtube and copied code exactly and I keep getting the error.

Does anyone have any ideas??!?!?!?!

heres my main.py:


from kivy.app import App
from kivy.lang import Builder
from kivy.uix.screenmanager import Screen, ScreenManager
from kivy.logger import Logger


class WindowManager(ScreenManager):
pass
class HomeScreen(Screen):
pass
class Settings(Screen):
pass
class QueryPage(Screen):
pass


try:
GUI = Builder.load_file('main.kv')
except Exception as e:
Logger.error(f"Failed to load main.kv: {e}")

raise
#
# GUI = Builder.load_file("main.kv")
class SQLTutor(App):
def build(self):
return GUI

def change_screen(self, screen_name):
# Change the screen by setting the current screen's name
self.root.current = screen_name


# def change_screen(self, screen_name):
# print(self.root.ids)
# # screen_manager = self.root.ids


if __name__ == "__main__":
SQLTutor().run()

and also my main.kv:


#:kivy 2.3.1

WindowManager:
HomeScreen:
name: 'home_screen'
id: home_screen
Settings:
name: 'settings'
id: settings
QueryPage:
name: 'query_page'
id: query_page

<HomeScreen>:
BoxLayout:
orientation: 'vertical'
size: root.width, root.height
Button:
text: 'You are on the Home Screen'
on_release: app.change_screen('settings')

<Settings>:
BoxLayout:
orientation: 'vertical'
size: root.width, root.height
Button:
text: 'You are on the Settings Screen'
on_release: app.change_screen('query_page')

<QueryPage>:
BoxLayout:
orientation: 'vertical'
size: root.width, root.height
Button:
text: 'You are on the Query Page'
on_release: app.change_screen('home_screen')


I've been working for 4 hrs trying to figure it out and I keep getting the same error.

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