How can I remove widgets in my main.kv file?

I have had a decent look around and haven't been able to find a solution for my problem. In my main.kv file, I have "home_screen" and "settings_screen" widget buttons that are displayed constantly (regardless of what screen the user is on).

The problem is that, when a user is not logged in and is on the "login_screen", these two buttons are there and remain active, allowing the user to simply access the "home_screen" or "settings_screen" before logging in.

What I'm trying to do is to remove these two widgets from the screen whenever the user is on the login screen. I fee like I'm on the right track but am maybe not referencing the widgets correctly. There are no errors arising, it simply doesn't do anything.

I have tried running my "if" statement and all it's necessary components in the change_screen() function and have also tried giving it its own function (shown in my example). I have tried it with a while statement (which seems to jam the app unless I put it in a thread). I have tried several different ways to reference the widgets and ways to write the remove_widget() line.

I have included the most basic functioning example I could so that someone may try run it themselves. Please help.

main.py

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

class HomeScreen(Screen):
    pass
class LoginScreen(Screen):
    pass

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

    def change_screen(self, screen_name):
        screen_manager = self.root.ids['screen_manager']
        screen_manager.current = screen_name
        self.home_setting_widgets(screen_name)

    def home_setting_widgets(self, screen_name):
        home_button = self.root.ids["home_button"]
        settings_button = self.root.ids["settings_button"]
        if screen_name == "login_screen":                  # if i'm on the login screen
            self.root.remove_widget(home_button)           # remove widgets
            self.root.remove_widget(settings_button)

TestApp().run()

main.kv

#:include kv/loginscreen.kv
#:include kv/homescreen.kv
GridLayout:
    cols: 1
    FloatLayout:
        GridLayout:
            rows: 1
            pos_hint: {"top": 1, "left": 1}
            size_hint: 1, .05
            Button:
                id: home_button
                text: "home"
            Button:
                id: settings_button
                text: "settings"
        ScreenManager:
            size_hint: 1, .95
            pos_hint: {"top": .95, "left": 1}
            id: screen_manager
            LoginScreen:
                name: "login_screen"
                id: login_screen
            HomeScreen:
                name: "home_screen"
                id: home_screen

loginscreen.kv

<LoginScreen>:
    FloatLayout:
        TextInput:
            size_hint: .7, .08
            pos_hint: {"top": .8, "center_x": .5}
        TextInput:
            size_hint: .7, .08
            pos_hint: {"top": .7, "center_x": .5}
        Button:
            text: "login"
            pos_hint:  {"top": .2, "center_x": .5}
            size_hint: .5, .08
            on_release:
                app.change_screen("home_screen")

homescreen.kv

<HomeScreen>:
    Button:
        text: "back"
        pos_hint:  {"top": .2, "center_x": .5}
        size_hint: .5, .08
        on_release:
            app.change_screen("login_screen")

This is a basic layout but still reproducible. Thank you :)

Solution

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

class HomeScreen(Screen):
    pass
class LoginScreen(Screen):
    pass

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

    def change_screen(self, screen_name):
        screen_manager = self.root.ids['screen_manager']
        screen_manager.current = screen_name
        self.home_setting_widgets(screen_name)

    def home_setting_widgets(self, screen_name):
        home_button = self.root.ids["home_button"]
        settings_button = self.root.ids["settings_button"]
        grid_layout = self.root.children[0].children[1]
        print("I remove from my widget, not from my root", grid_layout)
        if screen_name == "login_screen":  # if i'm on the login screen
            grid_layout.remove_widget(home_button)  # remove widgets
            grid_layout.remove_widget(settings_button)


TestApp().run()

I agree that there should be error message/warning.