import machine
import time
RED_LED_PIN = 1 #GP0
YELLOW_LED_PIN = 5 #GP1
GREEN_LED_PIN= 9 #GP2
red_led = machine.Pin(RED_LED_PIN,machine.Pin.OUT)
yellow_led = machine.Pin(YELLOW_LED_PIN,machine.Pin.OUT)
green_led= machine.Pin(GREEN_LED_PIN,machine.Pin.OUT)
def turn_on_led(led_pin):
    red_led.value(led_pin == RED_LED_PIN)
    yellow_led.value(led_pin == YELLOW_LED_PIN)
    green_led.value(led_pin == GREEN_LED_PIN)

while True:
    #Red light
    turn_on_led(RED_LED_PIN)
    time.sleep(5) #   Red light for 5 seconds 

    # Red and yellow lights (transition)
    turn_on_led(YELLOW_LED_PIN)
    time.sleep(2) #Red and yellow lights for 2 seconds

    #Green light 
    turn_on_led(GREEN_LED_PIN)
    time.sleep(5)  #Green light for 5 seconds 

    #Yellow light 
    turn_on_led(YELLOW_LED_PIN)
    time.sleep(2) #Yellow light for 2 seconds