code: def test_annotation_concat():
      """Test if two Annotations objects can be concatenated."""
      a = Annotations(
          [1, 2, 3],
          [5, 5, 8],
          ["a", "b", "c"],
          ch_names=[["1"], ["2"], []],
      )
      b = Annotations(
          [11, 12, 13],
          [1, 2, 2],
          ["x", "y", "z"],
          ch_names=[[], ["3"], []],
      )
  
      # test + operator (does not modify a or b)
      c = a + b
      assert_array_equal(c.onset, [1, 2, 3, 11, 12, 13])
      assert_array_equal(c.duration, [5, 5, 8, 1, 2, 2])
      assert_array_equal(c.description, ["a", "b", "c", "x", "y", "z"])
      assert_equal(len(a), 3)
      assert_equal(len(b), 3)
      assert_equal(len(c), 6)
  
      # c should have updated channel names
      want_names = np.array(
          [("1",), ("2",), (), (), ("3",), ()], dtype="O"
      )
      assert_array_equal(c.ch_names, want_names)
  
      # test += operator (modifies a in place)
      a += b
      assert_array_equal(a.onset, [1, 2, 3, 11, 12, 13])
      assert_array_equal(a.duration, [5, 5, 8, 1, 2, 2])
      assert_array_equal(a.description, ["a", "b", "c", "x", "y", "z"])
      assert_equal(len(a), 6)
      assert_equal(len(b), 3)
  
      # test += operator (modifies a in place)
      b._orig_time = _handle_meas_date(1038942070.7201)
      with pytest.raises(
          ValueError, match="orig_time should be the same"
      ):
          a += b
  
imports: import sys
  from collections import OrderedDict
  from datetime import datetime, timedelta, timezone
  from itertools import repeat
  from pathlib import Path
  import numpy
  import pytest
  from numpy.testing import assert_allclose, assert_array_almost_equal, assert_array_equal, assert_equal
  from pytest import approx
  import mne
  from mne import Annotations, Epochs, annotations_from_events, count_annotations, create_info, events_from_annotations, read_annotations
  from mne.annotations import _handle_meas_date, _read_annotations_txt_parse_header, _sync_onset
  from mne.datasets import testing
  from mne.io import RawArray, concatenate_raws, read_raw_fif
  from mne.utils import _dt_to_stamp, _raw_annot, _record_warnings, _stamp_to_dt, assert_and_remove_boundary_annot, catch_logging, check_version
label_desc: Use image node_id 15 for calling a global function with example usage: test_annotation_concat() without return types