import os, threading
lock = threading.Lock()
event = threading.Event()
def worker():
    for ct in range(4000):
        while not event.is_set():
            event.wait(1)
        with lock:
            event.clear()
def test():
    thread = threading.Thread(target=worker)
    thread.start()
    while thread.is_alive():
        with lock:
            event.set()
test()