code: def _check_train_test_split_y(fh, split):
      assert len(split) == 2
  
      train, test = split
      assert isinstance(train, pd.Series)
      assert isinstance(test, pd.Series)
      assert set(train.index).isdisjoint(test.index)
      for test_timepoint in test.index:
          assert np.all(train.index < test_timepoint)
      assert len(test) == len(fh)
      assert len(train) > 0
  
      cutoff = train.index[-1]
      np.testing.assert_array_equal(
          test.index, fh.to_absolute(cutoff).to_numpy()
      )
  
file_path: sktime/sktime/split/tests/test_temporaltraintest.py
imports: import numpy
  import pandas
  import pytest
  from sktime.datasets import load_airline
  from sktime.datatypes._utilities import get_cutoff
  from sktime.forecasting.tests._config import TEST_OOS_FHS, VALID_INDEX_FH_COMBINATIONS
  from sktime.split import temporal_train_test_split
  from sktime.utils._testing.forecasting import _make_fh
  from sktime.utils._testing.series import _make_series
label_desc: Use image node_id 1 for calling a global function with example usage: _check_train_test_split_y(fh, split) without return types