import gtk
 
def button_clicked(button):
    print 'Hello World!'
 
def main():
	window = gtk.Window()
	window.set_default_size(240, 180)
	window.set_title('Hello World!')
	window.connect('destroy', lambda w: gtk.main_quit())
 
	button = gtk.Button('Press Me')
	button.connect('clicked', button_clicked)
	button.show()
 
	window.add(button)
	window.present()
 
	gtk.main()
 
if __name__ == '__main__':
	main()