code: def test_pick_types_meg():
      """Test pick_types(meg=True)."""
      # info with MEG channels at indices 1, 2, and 4
      info1 = create_info(
          6, 256, ["eeg", "mag", "grad", "misc", "grad", "hbo"]
      )
  
      assert list(pick_types(info1, meg=True)) == [1, 2, 4]
      assert list(pick_types(info1, meg=True, eeg=True)) == [0, 1, 2, 4]
  
      assert list(pick_types(info1, meg=True)) == [1, 2, 4]
      assert not list(pick_types(info1, meg=False))  # empty
      assert list(pick_types(info1, meg="planar1")) == [2]
      assert not list(pick_types(info1, meg="planar2"))  # empty
  
      # info without any MEG channels
      info2 = create_info(
          6, 256, ["eeg", "eeg", "eog", "misc", "stim", "hbo"]
      )
  
      assert not list(pick_types(info2))  # empty
      assert list(pick_types(info2, eeg=True)) == [0, 1]
  
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 20 for calling a global function with example usage: test_pick_types_meg() without return types