code: def test_source(self):
      module = functions.import_string_code_as_module(
          cvsetting.group_k_fold["source"]
      )
      assert hasattr(module, "return_splits_iterable")
  
      generator = module.return_splits_iterable(self.X, self.y)
      self.assertRaises(ValueError, list, generator)
  
      del module
  
imports: from __future__ import absolute_import, print_function, division, unicode_literals
  import unittest
  from sklearn.datasets import load_iris
  from xcessiv import functions
  from xcessiv.presets import cvsetting
label_desc: Use image node_id 2 for calling the TestGroupKFold obj's underlying member method code with example usage: obj.test_source() without return types