python红绿灯倒计时

以下是一个Python红绿灯倒计时的例子：

import turtle
import time

# 定义函数，画出一个圆
def draw_circle(x, y, r, color):
    turtle.penup()
    turtle.goto(x, y)
    turtle.pendown()
    turtle.fillcolor(color)
    turtle.begin_fill()
    turtle.circle(r)
    turtle.end_fill()

# 定义函数，画出红灯
def draw_red_light(x, y, r):
    draw_circle(x, y, r, 'red')

# 定义函数，画出黄灯
def draw_yellow_light(x, y, r):
    draw_circle(x, y, r, 'yellow')

# 定义函数，画出绿灯
def draw_green_light(x, y, r):
    draw_circle(x, y, r, 'green')

# 定义函数，画出红绿灯
def draw_traffic_light(x, y):
    turtle.hideturtle()
    turtle.speed(0)
    turtle.penup()
    turtle.goto(x, y)
    turtle.pendown()
    turtle.pensize(3)
    turtle.fillcolor('gray')
    turtle.begin_fill()
    turtle.goto(x + 80, y)
    turtle.goto(x + 80, y + 180)
    turtle.goto(x, y + 180)
    turtle.goto(x, y)
    turtle.end_fill()
    draw_red_light(x + 40, y + 120, 30)
    draw_yellow_light(x + 40, y + 60, 30)
    draw_green_light(x + 40, y, 30)

# 定义函数，倒计时
def countdown(n):
    while n > 0:
        print(n)
        time.sleep(1)
        n -= 1

# 主函数
def main():
    draw_traffic_light(-200, 0)
    while True:
        draw_red_light(-160, 120, 30)
        countdown(5)
        draw_red_light(-160, 120, 30)
        draw_yellow_light(-160, 60, 30)
        countdown(2)
        draw_yellow_light(-160, 60, 30)
        draw_green_light(-160, 0, 30)
        countdown(5)
        draw_green_light(-160, 0, 30)
        draw_yellow_light(-160, 60, 30)
        countdown(2)
        draw_yellow_light(-160, 60, 30)

if __name__ == '__main__':
    main()