from machine import Pin
from time import sleep
led1=Pin(1,Pin.OUT)
led2=Pin(2,Pin.OUT)
led3=Pin(3,Pin.OUT)
while True:
    led1.value(1)
    led2.value(1)
    led3.value(1)
    sleep(1)
    led1.value(0)
    led2.value(0)
    led3.value(0)
    sleep(1)