human
I wrote the below code

    class EventHandler(FileSystemEventHandler, ):
        def on_modified(self, event):
            observer.unschedule(watch)
            unschedule_finished.set()
    unschedule_finished = Event()
    watch = observer.schedule(EventHandler(), u'')
    observer.start()
    (emitter,) = observer.emitters
    emitter.queue_event(FileModifiedEvent(u''))
    assert unschedule_finished.wait()
    assert (len(observer.emitters) == 0)

What's a good function header?
 Here's a good function header?
assistant
#Here's a good function header.

def test_unschedule_self(observer):