code: def __path_prefix(self, folder):
          
          path_parts = path_iter(folder)
          _skip_expected(path_parts, self.__base_folder_parts)
          result = "/".join(path_parts)
          if result:
              result += "/"
          return result
docs: Path prefix to be used when archiving any items from the given folder.
  
          Expects the folder to be located under the base folder path and the
          returned path prefix does not include the base folder information. This
          makes sure we include just the base folder's content in the archive,
          and not the base folder itself.