from machine import Pin
import utime

led1 = Pin(28,Pin.OUT)
led2 = Pin(21,Pin.OUT)
led3 = Pin(17,Pin.OUT)

led1.value(1)
utime.sleep(1)
led1.value(0)
utime.sleep(1)

led2.value(1)
utime.sleep(1)
led2.value(0)
utime.sleep(1)

led3.value(1)
utime.sleep(1)
led3.value(0)
utime.sleep(1)