code: def test_orig_units():
      """Test the error handling for original units."""
      # Should work fine
      info = create_info(ch_names=["Cz"], sfreq=100, ch_types="eeg")
      BaseRaw(info, last_samps=[1], orig_units={"Cz": "nV"})
  
      # Should complain that channel Cz does not have a corresponding original
      # unit.
      with pytest.raises(
          ValueError, match="has no associated original unit."
      ):
          info = create_info(ch_names=["Cz"], sfreq=100, ch_types="eeg")
          BaseRaw(info, last_samps=[1], orig_units={"not_Cz": "nV"})
  
      # Test that a non-dict orig_units argument raises a ValueError
      with pytest.raises(
          ValueError, match="orig_units must be of type dict"
      ):
          info = create_info(ch_names=["Cz"], sfreq=100, ch_types="eeg")
          BaseRaw(info, last_samps=[1], orig_units=True)
  
imports: import math
  import os
  import re
  from contextlib import redirect_stdout
  from io import StringIO
  from os import path
  from pathlib import Path
  import numpy
  import pytest
  from numpy.testing import assert_allclose, assert_array_almost_equal, assert_array_equal, assert_array_less
  import mne
  from mne import Annotations, concatenate_raws, create_info, pick_types
  from mne._fiff._digitization import DigPoint, _dig_kind_dict
  from mne._fiff.constants import FIFF
  from mne._fiff.meas_info import Info, _get_valid_units, _writing_info_hdf5
  from mne._fiff.pick import _ELECTRODE_CH_TYPES, _FNIRS_CH_TYPES_SPLIT
  from mne._fiff.proj import Projection
  from mne._fiff.utils import _mult_cal_one
  from mne.fixes import _numpy_h5py_dep
  from mne.io import BaseRaw, RawArray, read_raw_fif
  from mne.io.base import _get_scaling
  from mne.transforms import Transform
  from mne.utils import _import_h5io_funcs, _raw_annot, _stamp_to_dt, _TempDir, catch_logging, check_version, object_diff
label_desc: Use image node_id 3 for calling a global function with example usage: test_orig_units() without return types