new_contents: import RPi.GPIO as GPIO
  import time
  
  GPIO.setwarnings(False)
  GPIO.setmode(GPIO.BOARD)
  GPIO.setup(7,GPIO.OUT)
  GPIO.setup(11,GPIO.OUT)
  GPIO.setup(13,GPIO.OUT)
  while True:
      GPIO.output(7,True)
      GPIO.output(11,False)
      GPIO.output(13,False)
      time.sleep(0.5)
      GPIO.output(7,False)
      GPIO.output(11,True)
      GPIO.output(13,False)
      time.sleep(0.5)
      GPIO.output(7,False)
      GPIO.output(11,False)
      GPIO.output(13,True)
      time.sleep(0.5)
  
subject: Create blink_3led.py