code: def test_blend_array_shape():
      """[Base] BlendIndex: test the array shape on generation."""
      tr = np.array([0, 1])
      te = np.array([2, 3])
  
      for tri, tei in BlendIndex(0.45, 0.55, X=X).generate(
          as_array=True
      ):
          np.testing.assert_array_equal(tri, tr)
          np.testing.assert_array_equal(tei, te)
  
imports: import os
  import subprocess
  import numpy
  from mlens import config
  from mlens.utils import IdTrain
  from mlens.index import FoldIndex, BlendIndex, SubsetIndex, TemporalIndex, ClusteredSubsetIndex, FullIndex
  from mlens.index.base import partition, prune_train
label_desc: Use image node_id 24 for calling a global function with example usage: test_blend_array_shape() without return types