text: """Module contains validator functions."""
  
  
  def is_json_filename(filename: str) -> bool:
      """Check whether filename represents a json file.
  
      Args:
          filename:
              UNIX filename of .json file,
              for example - '/Users/king/urls.json'.
  
      Returns:
          Boolean, True if json filename is valid,
          otherwise False.
  
      Example:
          >>> is_json_filename_valid(filename='/Users/king/urls.json')
          >>> True
          >>> is_json_filename_valid(filename='/Users/king/urls.incorrectext')
          >>> False
      """
      valid_extension = '.json'
      extension = filename[-len(valid_extension):]
      return valid_extension == extension
  