code: def _check_expanding_windows(windows):
      n_splits = len(windows)
      for i in range(1, n_splits):
          current = windows[i]
          previous = windows[i - 1]
  
          assert current.shape[0] > previous.shape[0]
          assert current[0] == previous[0]
          assert current[-1] > previous[-1]
  
file_path: sktime/sktime/split/tests/test_expandingwindow.py
imports: import numpy
  import pytest
  from sktime.forecasting.tests._config import TEST_FHS, TEST_FHS_TIMEDELTA, TEST_STEP_LENGTHS, TEST_WINDOW_LENGTHS, TEST_YS
  from sktime.split import ExpandingWindowSplitter
  from sktime.split.base._common import _inputs_are_supported
  from sktime.split.tests.test_split import _check_cv, _get_n_incomplete_windows
  from sktime.utils.datetime import _coerce_duration_to_int
  from sktime.utils.validation.forecasting import check_fh
label_desc: Use image node_id 1 for calling a global function with example usage: _check_expanding_windows(windows) without return types