code: def test_bytes_io(pdf, config, hs, exported):
      """Test bti bytes-io API."""
      raw = read_raw_bti(pdf, config, hs, convert=True, preload=False)
  
      with open(pdf, "rb") as fid:
          pdf = BytesIO(fid.read())
      with open(config, "rb") as fid:
          config = BytesIO(fid.read())
      with open(hs, "rb") as fid:
          hs = BytesIO(fid.read())
  
      raw2 = read_raw_bti(pdf, config, hs, convert=True, preload=False)
      repr(raw2)
      assert_array_equal(raw[:][0], raw2[:][0])
  
imports: import os
  from collections import Counter
  from functools import partial, reduce
  from io import BytesIO
  from pathlib import Path
  import numpy
  import pytest
  from numpy.testing import assert_allclose, assert_array_almost_equal, assert_array_equal, assert_equal
  import mne
  from mne import pick_info, pick_types
  from mne._fiff._digitization import _make_bti_dig_points
  from mne._fiff.constants import FIFF
  from mne.datasets import testing
  from mne.io import read_raw_bti, read_raw_fif
  from mne.io.bti.bti import _check_nan_dev_head_t, _convert_coil_trans, _correct_trans, _get_bti_dev_t, _get_bti_info, _loc_to_coil_trans, _read_bti_header, _read_config, _read_head_shape, _rename_channels
  from mne.io.tests.test_raw import _test_raw_reader
  from mne.transforms import Transform, combine_transforms, invert_transform
  from mne.utils import assert_dig_allclose
label_desc: Use image node_id 9 for calling a global function with example usage: test_bytes_io(pdf, config, hs, exported) without return types