code: def test_no_ensemble(automl: AutoML) -> None:
      """
      Parameters
      ----------
      automl : AutoML
          A fitted automl object with ensemble size specified as 0
  
      Expects
      -------
      * Auto-sklearn does not load a model
      * The models_ should be of size 0
      * The cv_models_ should remain None
      """
      assert automl.ensemble_ is None
      assert len(automl.models_) == 0
      assert len(automl.cv_models_) == 0
  
file_path: auto-sklearn/test/test_automl/test_post_fit.py
imports: from pathlib import Path
  from autosklearn.automl import AutoML
  from autosklearn.ensemble_building.builder import CANDIDATES_FILENAME
  from pytest import mark
  from pytest_cases import parametrize_with_cases
  from pytest_cases.filters import has_tag
  import test.test_automl.cases
  from test.conftest import DEFAULT_SEED
label_desc: Use image node_id 3 for calling a global function with example usage: test_no_ensemble(automl) without return types