class_docstr: Generic DatasetBuilder loading from a directory.
class_docstr_tok: ["Generic","DatasetBuilder","loading","from","a","directory","."]
code: def _download_and_prepare(
      self, **kwargs
  ):  # pylint: disable=arguments-differ
      # DatasetBuilder.download_and_prepare is a no-op as self.data_dir already
      # exists.
      raise AssertionError("ReadOnlyBuilder can't be generated.")
  
imports: import functools
  import os
  import typing
  from typing import Any, List, Optional, Tuple, Type
  from etils import epath
  from tensorflow_datasets.core import dataset_builder
  from tensorflow_datasets.core import dataset_info
  from tensorflow_datasets.core import logging
  from tensorflow_datasets.core import naming
  from tensorflow_datasets.core import registered
  from tensorflow_datasets.core import splits
  from tensorflow_datasets.core import utils
  from tensorflow_datasets.core.features import feature
  from tensorflow_datasets.core.proto import dataset_info_pb2
  from tensorflow_datasets.core.utils import error_utils
  from tensorflow_datasets.core.utils import file_utils
  from tensorflow_datasets.core.utils import version
  from tensorflow_datasets.core.utils.lazy_imports_utils import tensorflow
label_desc: Use image node_id 6 for calling the ReadOnlyBuilder obj's underlying member method code with example usage: obj._download_and_prepare() without return types