code: def check_retrieval_twice(self, names, retrieval_func):
      self.cached_files = [
          os.path.join(self.root, name) for name in names
      ]
      train, test = retrieval_func(
          withlabel=self.withlabel, scale=self.scale
      )
  
      with mock.patch(
          "chainer.datasets.svhn.numpy", autospec=True
      ) as mnumpy:
          train, test = retrieval_func(
              withlabel=self.withlabel, scale=self.scale
          )
      mnumpy.savez_compressed.assert_not_called()  # creator() not called
      self.assertEqual(mnumpy.load.call_count, 2)
  
file_path: chainer/tests/chainer_tests/datasets_tests/test_svhn.py
imports: import os
  import unittest
  import mock
  import numpy
  from chainer.dataset import download
  from chainer.datasets import get_svhn
  from chainer.datasets import tuple_dataset
  from chainer import testing
  from chainer.testing import attr
label_desc: Use image node_id 6 for calling the TestSvhn obj's underlying member method code with example usage: obj.check_retrieval_twice(names, retrieval_func) without return types