from machine import Pin
import time
ledI = Pin(28, Pin.OUT)
ledS = Pin(27, Pin.OUT)
ledA = Pin(21, Pin.OUT)
while True:
    ledI.value(1)   #Se prende el LED rojo

    time.sleep(1)  #Se espera 1 segundo

    ledI.value(0)   #Se apaga el LED rojo

    ledS.value(1)   #Se prende el LED amarillo

    time.sleep(1)  #Se espera 1 segundo

    ledS.value(0)   #Se apaga el LED amarillo

    ledA.value(1)   #Se prende el LED verde

    time.sleep(1)  #Se espera 1 segundo

    ledA.value(0)   #Se apaga el LED verde