docs: def _find_combo_match(path):
      """
      Calculate the key to check the MEDIASYNC['JOINED'] dict for, perform the
      lookup, and return the matching key string if a match is found. If no
      match is found, return None instead.
      """
      key_str = _form_key_str(path)
      if not key_str:
          # _form_key_str() says this isn't even a CSS/JS file.
          return None
  
      if not msettings['JOINED'].has_key(key_str):
          # No combo file match found. Must be an single file.
          return None
      else:
          # Combo match found, return the JOINED key.
          return key_str