from machine import Pin
from time import sleep 

led_1=Pin(2,Pin.OUT)
led_2=Pin(3,Pin.OUT)
led_3=Pin(4,Pin.OUT)

while True:
    led_1.value(0)
    led_2.value(0)
    led_3.value(0)
    sleep(1)

    led_1.value(1)
    led_2.value(0)
    led_3.value(0)
    sleep(1)

    led_1.value(0)
    led_2.value(1)
    led_3.value(0)
    sleep(1)

    led_1.value(1)
    led-2.value(1)
    led_3.value(0)
    sleep(1)

    led_1.value(0)
    led_2.value(0)
    led_3.value(1)
    sleep(1)

    led_1.value(1)
    led_2.value(0)
    led_3,value(1)
    sleep(1)

    led_1.value(0)
    led_2.value(1)
    led_3.value(1)
    sleep(1)

    led_1.value(1)
    led_2.value(1)
    led_3.value(1)
    sleep(1)