import time,threading
event = threading.Event()
def lighter():
    count = 0
    event.set()#先设置绿灯
    while True:
        if 5 < count and count < 10:
            event.clear()#把标志位清了
            print("red light is on")
        elif count > 10:
            event.set()#变绿灯
            print("green light is on")
            count = 0
        else:
            print("green light is on")
        time.sleep(1)
        count += 1
def car(name):
    while True:
        if event.is_set():#代表绿灯
            print("%s running"%name)
            time.sleep(1)
        else:
            print("%s see the light is red ,waitting"%name)
            event.wait()
            print("%s see the light is green , going"%name)
light = threading.Thread(target=lighter,)
light.start()
car1 = threading.Thread(target=car,args=("tesla",))
car1.start()