如何在GTK3 (PyGObject)中动态更新widget？

import gi
gi.require_version('Gtk', '3.0')
from gi.repository import Gtk

def update_widget(widget, new_text):
    widget.set_text(new_text)

def main():
    window = Gtk.Window()
    window.connect("destroy", Gtk.main_quit)

    label = Gtk.Label()
    label.set_text("Initial Text")
    window.add(label)

    button = Gtk.Button()
    button.set_label("Update Text")
    button.connect("clicked", update_widget, label)
    window.add(button)

    window.show_all()
    Gtk.main()

if __name__ == "__main__":
    main()