old_contents: # re.IGNORECASE can be used for allowing user to type arbitrary cased texts.
  QUIT_NO_CASE = re.compile('quit', re.IGNORECASE)
  command = input('Type Command:')
  if QUIT_NO_CASE.match(command):
    print("Quiting...")
  
new_contents: # re.IGNORECASE can be used for allowing user to type arbitrary cased texts.
  QUIT_NO_CASE = re.compile('quit', re.IGNORECASE)
  command = input('Type Command:')
  if QUIT_NO_CASE.match(command):
    print("Quiting...")
  
  # Dissect multiple pieces from a string, using re.split.
  PHONE_NUMBER_REG = re.compile('(\d+)-(\d+)-(\d+)')
  # 0: area code, 1: extension1, 2: extension2
  items = PHONE_NUMBER_REG.split(phone_number)
  
subject: Update regex.py