My RootWidget(ScreenManager) isn't initializing my program with kivy/python

Question

I'm writing a python script with a kv script outside it for formatting.

I have 2 basic screens thus far. I can load 1 screen into a preview but things fall apart when I try 2 screens.

I get this error:

kivy.uix.screenmanager.ScreenManagerException: ScreenManager accepts only Screen widget.

Here's my python code:

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

Builder.load_file("design.kv")

class Intro(Screen):
    def go_settings(self):
        self.manager.current = "settings"
    pass

class Settings(Screen):
    print("In settings")
    pass

class RootWidget(ScreenManager):
    pass

class MainApp(App):
    def build(self):
        return RootWidget()

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

My kv code, titled "design.kv":

<Intro>:
GridLayout:
    cols: 1
    Label:
        text: "Intro"
    Button:
        text: "Settings"
        on_press: root.go_settings()


<Settings>:
    GridLayout:
        cols: 1
        Label:
            text: "Settings"

<RootWidget>:
    Intro:
        name: "intro"
    Settings:              #will work if I comment this line and below
        name: "settings" 

Not sure what's going on. Thanks for the help!

Answer 1

Alright, I think I got it.

I need to change the names of

Intro

and

Settings

to

IntroScreen

and

SettingsScreen

It seemed to work for me. Never thought the name I'd give would matter.