import machine import pin 
 import time

 # Define LEDs
 red=pin(3,pin.OUT)
 yellow=pin(9,pin.OUT)
 green=pin(15,pin.OUT)

 while True:
 red.value(1)
 yellow.value(0)
 green.value(0)
 time.sleep(5)

 red.value(0)
 yellow.value(1)
 green.value(0)
 time.sleep(3)

 red.value(0)
 yellow.value(0)
 green.value(0)
 time.sleep(5)