app/main.py

import flet as ft
from utils import views_handler


def main(page: ft.Page):
    page.title = 'BillPay'
    print("Initial route:", page.route)

    def route_change(e):
        print("Route change:", e.route)
        page.views.clear()
        page.views.append(
            views_handler(page)[page.route],
        )
        page.update()

    def view_pop(e):
        print("View pop:", e.view)
        page.views.pop()
        top_view = page.views[-1]
        page.go(top_view.route)

    page.on_route_change = route_change
    page.on_view_pop = view_pop
    page.go(page.route)


ft.app(target=main, assets_dir='assets')