code: def test_learner_transform():
      """[Module | LearnerEstimator] test transform"""
      p = est.transform(X)
      np.testing.assert_array_equal(p, F[:, [0]])
  
imports: import numpy
  from mlens.index import FoldIndex, FullIndex
  from mlens.utils.dummy import OLS, Scale
  from mlens.utils.exceptions import NotFittedError, ParameterChangeWarning
  from mlens.testing import Data
  from mlens.estimators import LearnerEstimator, TransformerEstimator, LayerEnsemble
  from mlens.externals.sklearn.base import clone
label_desc: Use image node_id 2 for calling a global function with example usage: test_learner_transform() without return types