from machine import Pin
from utime import sleep

red = Pin(1, Pin.OUT)
yellow = Pin(5, Pin.OUT)
green = Pin(9, Pin.OUT)

def leds_on():
    red.on()
    yellow.on()
    green.on()


def leds_off():
    red.off()
    yellow.off()
    green.off()


while True:
# all of and all on  at the same time
    leds_on()  
    sleep(0.8)  
    leds_off()  
    sleep(0.8)  
# the Traffic signal
    red.on()  
    sleep(0.8)  
    red.off()  
    yellow.on()  
    sleep(0.8)  
    yellow.off()  
    green.on()  
    sleep(0.8)  
    green.off()