code: def tearDown(self):
      if hasattr(self, "cached_train_file") and os.path.exists(
          self.cached_train_file
      ):
          os.remove(self.cached_train_file)
      if hasattr(self, "cached_test_file") and os.path.exists(
          self.cached_test_file
      ):
          os.remove(self.cached_test_file)
  
imports: import importlib
  import os
  import unittest
  import mock
  import numpy
  from chainer.dataset import download
  from chainer.datasets import get_fashion_mnist
  from chainer.datasets import get_fashion_mnist_labels
  from chainer.datasets import get_kuzushiji_mnist
  from chainer.datasets import get_kuzushiji_mnist_labels
  from chainer.datasets import get_mnist
  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 TestMnist obj's underlying member method code with example usage: obj.tearDown() without return types