Python GTK3:如何创建Gtk.FileChooseDialog？

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

def on_file_chooser_dialog_response(dialog, response):
    if response == Gtk.ResponseType.OK:
        print("File selected: ", dialog.get_filename())
    dialog.destroy()

dialog = Gtk.FileChooserDialog(
    title="Select a file",
    parent=None,
    action=Gtk.FileChooserAction.OPEN,
    buttons=(
        Gtk.STOCK_CANCEL,
        Gtk.ResponseType.CANCEL,
        Gtk.STOCK_OPEN,
        Gtk.ResponseType.OK
    )
)
dialog.connect("response", on_file_chooser_dialog_response)
dialog.run()