code: def test_subset_raises_on_w_raise_():
      """[Base] SubsetIndex: check raises on n_part = 1, folds = 1."""
      with np.testing.assert_raises(ValueError):
          SubsetIndex(1, 1, X=X)
  
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 40 for calling a global function with example usage: test_subset_raises_on_w_raise_() without return types