code: def tearDown(self):
      if hasattr(self, "cached_file") and os.path.exists(
          self.cached_file
      ):
          os.remove(self.cached_file)
  
imports: import os
  import unittest
  import mock
  import numpy
  from chainer.dataset import download
  from chainer.datasets import get_cifar10
  from chainer.datasets import get_cifar100
  from chainer.datasets import tuple_dataset
  from chainer import testing
  from chainer.testing import attr
label_desc: Use image node_id 2 for calling the TestCifar obj's underlying member method code with example usage: obj.tearDown() without return types