如何在Gtk Python中关注条目时更改输入语言

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

window = Gtk.Window()
window.set_title("Change Input Language")
window.set_default_size(200, 100)

box = Gtk.Box(orientation=Gtk.Orientation.HORIZONTAL, spacing=6)
window.add(box)

label = Gtk.Label()
label.set_text("Select Input Language:")
box.pack_start(label, True, True, 0)

combo = Gtk.ComboBoxText()
combo.append_text("English")
combo.append_text("Chinese")
box.pack_start(combo, True, True, 0)

def on_combo_changed(combo):
    active_text = combo.get_active_text()
    if active_text == "English":
        # Change input language to English
        # Code to change input language goes here
    elif active_text == "Chinese":
        # Change input language to Chinese
        # Code to change input language goes here

combo.connect("changed", on_combo_changed)

window.show_all()
Gtk.main()