code: def test_shuffle():
      """[Parallel] Test shuffle between layers."""
      h, s = X.copy(), y.copy()
      for i in range(3):
          h, s = _shuffled(h, s, ens4.layers[i].random_state)
          h = ens5.fit(h, s, return_preds=True)
  
      z = ens4.fit(X, y, return_preds=True)
  
      np.testing.assert_array_equal(h.astype(np.float32), z)
  
file_path: mlens/mlens/parallel/tests/test_c_multi_sparse_feature_prop.py
imports: import numpy
  from scipy.sparse import csr_matrix
  from mlens.index import FoldIndex
  from mlens.ensemble.base import BaseEnsemble
  from mlens.externals.sklearn.validation import check_random_state
  from mlens.utils.dummy import OLS
label_desc: Use image node_id 6 for calling a global function with example usage: test_shuffle() without return types