当gtk.paned滑块的位置发生变化时如何通知？

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

def on_position_changed(widget, gparam):
    print("滑块位置已更改为：", widget.get_position())

window = Gtk.Window()
window.set_title("Paned 示例")
window.set_default_size(400, 300)

paned = Gtk.Paned(orientation=Gtk.Orientation.HORIZONTAL)

child1 = Gtk.Label(label="子窗口1")
child2 = Gtk.Label(label="子窗口2")

paned.add1(child1)
paned.add2(child2)

window.add(paned)

paned.connect("notify::position", on_position_changed)

window.show_all()

window.connect("destroy", Gtk.main_quit)

Gtk.main()