code: def test_layer_attr():
      """[Module | LayerEnsemble] test setting attribute"""
  
      def fitted():
          est.__fitted__
  
      est.propagate_features = [0]
      np.testing.assert_warns(ParameterChangeWarning, fitted)
  
      # If this fails, it is trying to propagate feature but predict_out is None!
      est.fit(X, y)
      np.testing.assert_no_warnings(fitted)
  
imports: import numpy
  from mlens.index import FullIndex, FoldIndex
  from mlens.testing import Data
  from mlens.testing.dummy import ESTIMATORS, PREPROCESSING
  from mlens.utils.dummy import OLS, Scale
  from mlens.utils.exceptions import NotFittedError, ParameterChangeWarning
  from mlens.parallel import make_group
  from mlens.estimators import LearnerEstimator, TransformerEstimator, LayerEnsemble
  from mlens.externals.sklearn.base import clone
label_desc: Use image node_id 7 for calling a global function with example usage: test_layer_attr() without return types