from machine import Pin
import time

red_led = 9
yellow_led = 10
green_led = 11

red = Pin(red_led, Pin.OUT)
yellow = Pin(yellow_led, Pin.OUT)
green = Pin(green_led, Pin.OUT)

def traffic_light():
    while True:
        red.value(1)
        yellow.value(0)
        green.value(0)
        time.sleep(5)

        red.value(0)
        yellow.value(1)
        green.value(0)
        time.sleep(2)

        red.value(0)
        yellow.value(0)
        green.value(1)
        time.sleep(5)

        red.value(0)
        yellow.value(1)
        green.value(0)
        time.sleep(2)

traffic_light()