code: def test_serialization(self):
      import faiss
  
      dset: Dataset = self._create_dummy_dataset()
      dset.add_faiss_index_from_external_arrays(
          external_arrays=np.ones((30, 5))
          * np.arange(30).reshape(-1, 1),
          index_name="vecs",
          metric_type=faiss.METRIC_INNER_PRODUCT,
      )
  
      # Setting delete=False and unlinking manually is not pretty... but it is required on Windows to
      # ensure somewhat stable behaviour. If we don't, we get PermissionErrors. This is an age-old issue.
      # see https://bugs.python.org/issue14243 and
      # https://stackoverflow.com/questions/23212435/permission-denied-to-write-to-my-temporary-file/23212515
      with tempfile.NamedTemporaryFile(delete=False) as tmp_file:
          dset.save_faiss_index("vecs", tmp_file.name)
          dset.load_faiss_index("vecs2", tmp_file.name)
      os.unlink(tmp_file.name)
  
      scores, examples = dset.get_nearest_examples(
          "vecs2", np.ones(5, dtype=np.float32)
      )
      self.assertEqual(examples["filename"][0], "my_name-train_29")
  
imports: import os
  import tempfile
  from functools import partial
  from unittest import TestCase
  from unittest.mock import patch
  import numpy
  import pytest
  from datasets.arrow_dataset import Dataset
  from datasets.search import ElasticSearchIndex, FaissIndex, MissingIndex
  from .utils import require_elasticsearch, require_faiss
label_desc: Use image node_id 4 for calling the IndexableDatasetTest obj's underlying member method code with example usage: obj.test_serialization() without return types