code: def test_inverse_operator_discrete(evoked, tmp_path):
      """Test MNE inverse computation on discrete source space."""
      # Make discrete source space
      src = mne.setup_volume_source_space(
          pos=dict(
              rr=[[0, 0, 0.1], [0, -0.01, 0.05]],
              nn=[[0, 1, 0], [1, 0, 0]],
          ),
          bem=fname_bem,
      )
  
      # Perform inverse
      fwd = mne.make_forward_solution(
          evoked.info, mne.Transform("head", "mri"), src, fname_bem
      )
      inv = make_inverse_operator(
          evoked.info,
          fwd,
          make_ad_hoc_cov(evoked.info),
          loose=0,
          fixed=True,
          depth=0,
      )
      stc = apply_inverse(evoked, inv)
      assert isinstance(stc, VolSourceEstimate)
      assert stc.data.shape == (2, len(evoked.times))
  
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 25 for calling a global function with example usage: test_inverse_operator_discrete(evoked, tmp_path) without return types