import gi

gi.require_version("Gtk", "4.0")
from gi.repository import Gtk


def on_menu_item_activate(menu_item):
    print(f"{menu_item.get_label()} was activated")


app = Gtk.Application(application_id="com.example.GtkApplication")


def on_activate(app):
    window = Gtk.ApplicationWindow(application=app)
    menu_bar = Gtk.MenuBar()

    menu_item_file = Gtk.MenuItem(label="File")
    submenu_file = Gtk.Menu()
    menu_item_new = Gtk.MenuItem(label="New")
    menu_item_open = Gtk.MenuItem(label="Open")
    menu_item_exit = Gtk.MenuItem(label="Exit")

    menu_item_new.connect("activate", on_menu_item_activate)
    menu_item_open.connect("activate", on_menu_item_activate)
    menu_item_exit.connect("activate", on_menu_item_activate)

    submenu_file.append(menu_item_new)
    submenu_file.append(menu_item_open)
    submenu_file.append(menu_item_exit)
    menu_item_file.set_submenu(submenu_file)
    menu_bar.append(menu_item_file)

    window.set_child(menu_bar)

    window.present()


app.connect("activate", on_activate)
app.run(None)