code: def test_inverse_operator_volume(evoked, tmp_path):
      """Test MNE inverse computation on volume source space."""
      inv_vol = read_inverse_operator(fname_vol_inv)
      assert repr(inv_vol)
      stc = apply_inverse(evoked, inv_vol, lambda2, "dSPM")
      assert isinstance(stc, VolSourceEstimate)
      # volume inverses don't have associated subject IDs
      assert stc.subject is None
      stc.save(tmp_path / "tmp-vl.stc")
      stc2 = read_source_estimate(tmp_path / "tmp-vl.stc")
      assert np.all(stc.data > 0)
      assert np.all(stc.data < 35)
      assert_array_almost_equal(stc.data, stc2.data)
      assert_array_almost_equal(stc.times, stc2.times)
      # vector source estimate
      stc_vec = apply_inverse(
          evoked, inv_vol, lambda2, "dSPM", "vector"
      )
      assert repr(stc_vec)
      assert_allclose(np.linalg.norm(stc_vec.data, axis=1), stc.data)
      with pytest.raises(RuntimeError, match="surface or discrete"):
          apply_inverse(evoked, inv_vol, pick_ori="normal")
  
imports: import copy
  import re
  from pathlib import Path
  import numpy
  import pytest
  from numpy.testing import assert_allclose, assert_array_almost_equal, assert_array_equal, assert_array_less, assert_equal
  from scipy import sparse
  import mne
  from mne import Covariance, EvokedArray, SourceEstimate, combine_evoked, compute_raw_covariance, convert_forward_solution, make_ad_hoc_cov, make_forward_solution, make_sphere_model, pick_channels_forward, pick_types, pick_types_forward, read_cov, read_evokeds, read_forward_solution
  from mne.datasets import testing
  from mne.epochs import Epochs, EpochsArray, make_fixed_length_epochs
  from mne.event import read_events
  from mne.forward import apply_forward, is_fixed_orient, restrict_forward_to_stc
  from mne.io import read_info, read_raw_fif
  from mne.label import label_sign_flip, read_label
  from mne.minimum_norm import INVERSE_METHODS, apply_inverse, apply_inverse_cov, apply_inverse_epochs, apply_inverse_raw, apply_inverse_tfr_epochs, compute_rank_inverse, make_inverse_operator, prepare_inverse_operator, read_inverse_operator, write_inverse_operator
  from mne.source_estimate import VolSourceEstimate, read_source_estimate
  from mne.source_space._source_space import _get_src_nn
  from mne.surface import _normal_orth
  from mne.time_frequency import EpochsTFR
  from mne.utils import _record_warnings, catch_logging
label_desc: Use image node_id 24 for calling a global function with example usage: test_inverse_operator_volume(evoked, tmp_path) without return types