from machine import Pin
from time import sleep

led_red = Pin(1, Pin.OUT)
led_yellow = Pin(2, Pin.OUT)
led_green = Pin(3, Pin.OUT)


while True : 
    led_red.value(1)
    led_yellow.value(0)
    led_green.value(0)
    sleep(1)
    led_red.value(0)
    led_yellow.value(1)
    led_green.value(0)
    sleep(1)
    led_red.value(0)
    led_yellow.value(0)
    led_green.value(1)
    sleep(1)