code: def is_initialized(self):
      return self._index_initialized
  
imports: import os
  import pickle
  import time
  from typing import Iterable, List, Optional, Tuple
  import numpy
  from ...tokenization_utils import PreTrainedTokenizer
  from ...tokenization_utils_base import BatchEncoding
  from ...utils import cached_file, is_datasets_available, is_faiss_available, logging, requires_backends
  from .configuration_rag import RagConfig
  from .tokenization_rag import RagTokenizer
label_desc: Use image node_id 4 for calling the HFIndexBase obj's underlying member method code with example usage: obj.is_initialized() and returns: self