code: def test_crop_append():
      """Test crop and append raw."""
      raw = _test_raw_reader(
          read_raw_bti,
          pdf_fname=pdf_fnames[0],
          config_fname=config_fnames[0],
          head_shape_fname=hs_fnames[0],
      )
      y, t = raw[:]
      t0, t1 = 0.25 * t[-1], 0.75 * t[-1]
      mask = (t0 <= t) * (t <= t1)
      raw_ = raw.copy().crop(t0, t1)
      y_, _ = raw_[:]
      assert y_.shape[1] == mask.sum()
      assert y_.shape[0] == y.shape[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 4 for calling a global function with example usage: test_crop_append() without return types