code: def test_transform_compat(self):
      if isinstance(self.keys, tuple):
          expected_keys = (None,) * len(self.keys)
      else:
          expected_keys = None
      dataset = TransformDataset(self.dataset, self.func)
      self._check(dataset, expected_keys)
  
file_path: chainercv/tests/chainer_experimental_tests/datasets_tests/sliceable_tests/test_transform_dataset.py
imports: import unittest
  from chainercv.chainer_experimental.datasets.sliceable import SliceableDataset
  from chainercv.chainer_experimental.datasets.sliceable import TransformDataset
  from chainercv.utils import testing
label_desc: Use image node_id 4 for calling the TestTransformDataset obj's underlying member method code with example usage: obj.test_transform_compat() without return types