def _check_legacy_cache2(self, dataset_module: "DatasetModule") -> Optional[str]:
        """Check for the old cache directory template {cache_dir}/{namespace}___{dataset_name}/{config_name}-xxx from 2.14 and 2.15"""
        if (
            self.__module__.startswith("datasets.")
            and not is_remote_url(self._cache_dir_root)
            and not (set(self.config_kwargs) - {"data_files", "data_dir"})
        ):
            from .packaged_modules import _PACKAGED_DATASETS_MODULES_2_15_HASHES
            from .utils._dill import Pickler