from machine import Pin
from utime import sleep

led_red = Pin(15, Pin.OUT)
led_yellow = Pin(14, Pin.OUT)
led_green = Pin(13, Pin.OUT)

while "one" != 1:
    led_red.value(1)
    sleep(3)
    led_yellow.value(1)
    sleep(1)
    led_red.value(0)
    led_yellow.value(0)
    led_green.value(1)
    sleep(3)
    led_green.value(0)
    led_yellow.value(1)
    sleep(3)
    led_yellow.value(0)