from machine import Pin
import time
led1=Pin(15,Pin.OUT)
led2=Pin(4,Pin.OUT)
led3=Pin(22,Pin.OUT)

while True:
    led1.value(1)
    time.sleep(1)
    led1.value(0)
    led2.value(1)
    time.sleep(1)
    led2.value(0)
    led3.value(1)
    time.sleep(1)
    led3 .value(0)