code: def test_not_specified_train_size_n_splits(X, y, group_numbers):
      cv_args = {"test_size": 1}
      expected_results = None
      error_message = "Either train_size or n_splits should be defined"
  
      with pytest.raises(ValueError, match=error_message):
          check_splits(X, y, group_numbers, cv_args, expected_results)
  
imports: import numpy
  import pytest
  from sklearn.dummy import DummyClassifier
  from sklearn.model_selection import cross_val_score
  from mlxtend.evaluate import GroupTimeSeriesSplit
label_desc: Use image node_id 21 for calling a global function with example usage: test_not_specified_train_size_n_splits(X, y, group_numbers) without return types