code: def test_sessions():
      """Test the sessions vector."""
      data = np.ones((40, 40, 40, 4))
      # Create a border, so that the masking work well
      data[0] = 0
      data[-1] = 0
      data[:, -1] = 0
      data[:, 0] = 0
      data[..., -1] = 0
      data[..., 0] = 0
      data[20, 20, 20] = 1
      data_img = nibabel.Nifti1Image(data, np.eye(4))
      masker = NiftiMasker(runs=np.ones(3, dtype=int))
      with pytest.raises(ValueError):
          masker.fit_transform(data_img)
  
imports: import os
  import shutil
  import warnings
  from tempfile import mkdtemp
  import nibabel
  import numpy
  import pytest
  from numpy.testing import assert_array_equal
  from nilearn._utils import data_gen, exceptions, testing
  from nilearn._utils.class_inspect import get_params
  from nilearn.image import get_data, index_img
  from nilearn.maskers import NiftiMasker
  from nilearn.maskers.nifti_masker import _filter_and_mask
label_desc: Use image node_id 14 for calling a global function with example usage: test_sessions() without return types