#!/usr/bin/env python
# -*- coding: utf-8 -*-

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

def on_activate(app):
    win = Gtk.ApplicationWindow(application=app)
    btn = Gtk.Button(label="Hello, World!")
    btn.connect('clicked', lambda x: win.destroy())
    win.add(btn)
    win.show_all()

def main(args):
    app = Gtk.Application(application_id='org.gtk.Example')
    app.connect('activate', on_activate)
    app.run(None)
    return 0

if __name__ == '__main__':
    import sys
    sys.exit(main(sys.argv))