import time,threading

event = threading.Event()

def lighter():
    count =0
    event.set()#先設定紅綠燈,設定一個全域性變數標誌位
    while True:
        if count >5 and count<10:#改成紅燈
            event.clear()#把標誌位清理，設定是TRUE，清空是false
            print("\033[41;1mred light is on ...\033[0m")
        elif count>10:
            event.set()#變綠燈
 
            count = 0
        else:
            print("\033[42;1mgreen light is on ...\033[0m")
        time.sleep(1)
        count +=1
def car(name):
    while True:
        if event.is_set():#代表綠燈
            print("[%s] running ..."%name)
            time.sleep(1)
        else:
            print("[%s] sees red light,waiting..."%name)
 
            event.wait()#去檢測，標誌位沒有設定，卡在這
            print("\033[34;1m[%s] green light is on ,start going ...\033[0m"%name)

light = threading.Thread(target=lighter,)
light.start()

car1 = threading.Thread(target=car,args=('BMW',))
car1.start()