old_contents: # -*- coding: utf-8 -*-
  
  """This module is provide internal util functions."""
  
  import ssl
  from os import path
  from typing import Union
  from urllib import request
  from uuid import uuid4
  
  __all__ = ['luhn_checksum']
  
  
  def luhn_checksum(num: str) -> str:
      """Calculate a checksum for num using the Luhn algorithm.
  
      :param num: The number to calculate a checksum for as a string.
      :return: Checksum for number.
      """
      check = 0
      for i, s in enumerate(reversed(num)):
          sx = int(s)
          sx = sx * 2 if i % 2 == 0 else sx
          sx = sx - 9 if sx > 9 else sx
          check += sx
      return str(check * 9 % 10)
  
new_contents: # -*- coding: utf-8 -*-
  
  """This module is provide internal util functions."""
  
  __all__ = ['luhn_checksum']
  
  
  def luhn_checksum(num: str) -> str:
      """Calculate a checksum for num using the Luhn algorithm.
  
      :param num: The number to calculate a checksum for as a string.
      :return: Checksum for number.
      """
      check = 0
      for i, s in enumerate(reversed(num)):
          sx = int(s)
          sx = sx * 2 if i % 2 == 0 else sx
          sx = sx - 9 if sx > 9 else sx
          check += sx
      return str(check * 9 % 10)
  
subject: Remove unsused imports