docs: def get_cached_files(url, server_name="", document_root=None):
      """
      Given a URL, return a list of paths of all cached variations of that file.
  
      Doesn't include the original file.
      """
      import glob
      url_info = process_url(url, server_name, document_root, check_security=False)
  
      # get path to cache directory with basename of file (no extension)
      filedir = os.path.dirname(url_info['requested_file'])
      fileglob = '{0}*{1}'.format(url_info['base_filename'], url_info['ext'])
      return glob.glob(os.path.join(filedir, fileglob))