import RPi.GPIO as GPIO
import time

led_pin = 19

def setup(led):
    GPIO.setmode(GPIO.BCM)
    GPIO.setup(led, GPIO.OUT)

def led_on(led):
    GPIO.output(led, GPIO.HIGH)

def led_off(led):
    GPIO.output(led, GPIO.LOW)

def main():
    setup(led_pin)
    while True:
        led_on(led_pin)
        time.sleep(0.3)
        led_off(led_pin)
        time.sleep(0.3)