code: def test_subset_warns_on_wo_raise_():
      """[Base] SubsetIndex: check raises on n_part = 1, folds = 1."""
      with np.testing.assert_warns(UserWarning):
          SubsetIndex(1, 1, raise_on_exception=False, 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 39 for calling a global function with example usage: test_subset_warns_on_wo_raise_() without return types