code: def test_clone():
      """[Parallel | Learner] Testing cloning"""
      lr = Learner(OLS(), indexer=data.indexer, name="lr")
      l = clone(lr)
      l.set_indexer(data.indexer)
  
      assert not l.__fitted__
  
      F = _run(l, "fit", X, y, return_preds=True)
      H = _run(lr, "fit", X, y, return_preds=True, refit=False)
      np.testing.assert_array_equal(F, H)
  
imports: import numpy
  from mlens.testing import Data, EstimatorContainer
  from mlens.parallel import Group, Learner, Pipeline, run
  from mlens.utils.dummy import OLS, Scale
  from mlens.externals.sklearn.base import clone
label_desc: Use image node_id 4 for calling a global function with example usage: test_clone() without return types