code: def test_get_cv():
      get_cv(None)
      get_cv(4)
      get_cv(KFold())
  
      with pytest.raises(ValueError):
          get_cv(23.2)
      with pytest.raises(ValueError):
          get_cv("bad")
  
file_path: Surprise/tests/test_split.py
imports: import os
  from collections import Counter
  from copy import copy
  import numpy
  import pytest
  from surprise import Dataset, Reader
  from surprise.model_selection import KFold, LeaveOneOut, PredefinedKFold, RepeatedKFold, ShuffleSplit, train_test_split
  from surprise.model_selection.split import get_cv
label_desc: Use image node_id 7 for calling a global function with example usage: test_get_cv() without return types