code: def test_exception_in_fetch(self):
      class LevelCache(object):
          def fetch(self, key, pk3_path):
              del key
              del pk3_path
              raise ValueError("foo")
  
          def write(self, key, pk3_path):
              pass
  
      env = self._create_environment(LevelCache())
      with six.assertRaisesRegex(self, ValueError, "foo"):
          env.reset(episode=1, seed=123)
          env.step(self._dummy_action)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import os
  import shutil
  import six
  import tempfile
  from absl.testing import absltest
  import numpy
  import deepmind_lab
label_desc: Use image node_id 7 for calling the LevelCacheTest obj's underlying member method code with example usage: obj.test_exception_in_fetch() without return types