code: def is_stone_backend(cls, path):
          
          path_without_ext, _ = os.path.splitext(path)
          _, second_ext = os.path.splitext(path_without_ext)
          return second_ext == cls.backend_extension
docs: Returns True if the file name matches the format of a stone backend,
          ie. its inner extension of "stoneg". For example: xyz.stoneg.py