code: def test_check_ensemble_build_lc_none_no_raise_():
      """[Utils] check_ensemble_build : raises warning on LC None + no raise_."""
      lc = clone(LAYER_CONTAINER)
      lc.stack = None
      lc.raise_on_exception = False
  
      FLAG = np.testing.assert_warns(
          LayerSpecificationWarning, check_ensemble_build, lc
      )
      assert FLAG is False
  
imports: import numpy
  from mlens.externals.sklearn.base import clone
  from mlens.utils.checks import check_ensemble_build, assert_valid_estimator, assert_correct_format, check_initialized
  from mlens.utils.dummy import OLS, Scale
  from mlens.testing import EstimatorContainer
  from mlens.utils.exceptions import LayerSpecificationError, LayerSpecificationWarning, NotFittedError, ParallelProcessingError, ParallelProcessingWarning
label_desc: Use image node_id 4 for calling a global function with example usage: test_check_ensemble_build_lc_none_no_raise_() without return types