code: def test_pick_dbs():
      """Test picking with DBS."""
      # gh-8739
      names = "A1 A2 Fz O OTp1 OTp2 OTp3".split()
      types = "mag mag eeg eeg dbs dbs dbs".split()
      info = create_info(names, 1024.0, types)
      picks_by_type = [
          ("mag", [0, 1]),
          ("eeg", [2, 3]),
          ("dbs", [4, 5, 6]),
      ]
      assert_indexing(info, picks_by_type)
      assert_array_equal(
          pick_types(info, meg=False, dbs=True), [4, 5, 6]
      )
      for i, t in enumerate(types):
          assert channel_type(info, i) == types[i]
      raw = RawArray(np.zeros((len(names), 7)), info)
      events = np.array([[1, 0, 0], [2, 0, 0]])
      epochs = Epochs(
          raw,
          events=events,
          event_id={"event": 0},
          tmin=-1e-5,
          tmax=1e-5,
          baseline=(0, 0),
      )  # only one sample
      evoked = epochs.average(
          pick_types(epochs.info, meg=True, dbs=True)
      )
      e_dbs = evoked.copy().pick(picks="dbs")
      for lt, rt in zip(e_dbs.ch_names, [names[4], names[5], names[6]]):
          assert lt == rt
      raw = read_raw_fif(
          io_dir / "tests" / "data" / "test_chpi_raw_sss.fif"
      )
      assert len(pick_types(raw.info, meg=False, dbs=True)) == 0
  
imports: from copy import deepcopy
  from pathlib import Path
  import numpy
  import pytest
  from numpy.testing import assert_array_equal
  from mne import Epochs, channel_indices_by_type, channel_type, create_info, make_ad_hoc_cov, pick_channels, pick_channels_cov, pick_channels_regexp, pick_info, pick_types, pick_types_forward, read_forward_solution, rename_channels
  from mne._fiff.constants import FIFF
  from mne._fiff.pick import _DATA_CH_TYPES_SPLIT, _contains_ch_type, _picks_by_type, _picks_to_idx, get_channel_type_constants
  from mne.channels import make_standard_montage
  from mne.datasets import testing
  from mne.io import RawArray, read_info, read_raw_bti, read_raw_fif, read_raw_kit
  from mne.preprocessing import compute_current_source_density
  from mne.utils import assert_object_equal, catch_logging
label_desc: Use image node_id 8 for calling a global function with example usage: test_pick_dbs() without return types