def onChange(ev):
    cmd = ['/bin/echo', 'File', ev.pathname, 'changed']
subprocess.Popen(cmd).communicate()
wm = pyinotify.WatchManager()
wm.add_watch('file.watched', pyinotify.IN_MODIFY, onChange)
notifier = pyinotify.Notifier(wm)
notifier.loop()
how to make pyinotify to run a program on any modification over a file?