code: def test_fetch_atlas_talairach(tmp_path, request_mocker):
      request_mocker.url_mapping[
          "*talairach.nii"
      ] = _get_small_fake_talairach()
      level_values = np.ones((81, 3)) * [0, 1, 2]
      talairach = atlas.fetch_atlas_talairach(
          "hemisphere", data_dir=tmp_path
      )
  
      assert talairach.description != ""
  
      assert_array_equal(
          get_data(talairach.maps).ravel(), level_values.T.ravel()
      )
      assert_array_equal(talairach.labels, ["Background", "b", "a"])
  
      talairach = atlas.fetch_atlas_talairach("ba", data_dir=tmp_path)
  
      assert talairach.description != ""
  
      assert_array_equal(
          get_data(talairach.maps).ravel(), level_values.ravel()
      )
  
      with pytest.raises(ValueError):
          atlas.fetch_atlas_talairach("bad_level")
  
imports: import itertools
  import os
  import re
  from pathlib import Path
  import nibabel
  import numpy
  import pandas
  import pytest
  from numpy.testing import assert_array_equal
  from nilearn._utils import data_gen
  from nilearn._utils.testing import serialize_niimg
  from nilearn.conftest import _rng
  from nilearn.datasets import atlas
  from nilearn.datasets._utils import fetch_files
  from nilearn.datasets.tests._testing import dict_to_archive
  from nilearn.image import get_data
label_desc: Use image node_id 28 for calling a global function with example usage: test_fetch_atlas_talairach(tmp_path, request_mocker) without return types