Python Watchdog: The meaning of time.sleep(1)

Question

I am learning the watchdog package in python, I this is the example code I found in document.

I am wondering why time.sleep is necessary in here, I my point of view, that will stop the process. What is the meaning when it occur in here ?

if __name__ == "__main__":
    logging.basicConfig(level=logging.INFO,
                        format='%(asctime)s - %(message)s',
                        datefmt='%Y-%m-%d %H:%M:%S')
    path = sys.argv[1] if len(sys.argv) > 1 else '.'
    event_handler = LoggingEventHandler()
    observer = Observer()
    observer.schedule(event_handler, path, recursive=True)
    observer.start()
    try:
        while True:
            time.sleep(1)
    finally:
        observer.stop()
        observer.join()