python gpio script to blink led

led-blink.py

# import the library that allows us to logically access the GPIO pins
# refer to the library as GPIO, it is like an alias
import RPi.GPIO as GPIO
import time

# use the BCIM numbering scheme
GPIO.setmode(GPIO.BCM)

# set pin 18 to be in output mode
GPIO.setup(18, GPIO.OUT)

run = True

while(run):
  try:
    GPIO.output(18, GPIO.HIGH)
    time.sleep(.5)
    GPIO.output(18, GPIO.LOW)
    time.sleep(.5)
  except KeyboardInterrupt:
    run = False
    GPIO.cleanup()
    print