code: def tearDown(self):
      accelerator_util.shutdown_accelerator_system()
      super().tearDown()
  
imports: from tensorflow.dtensor.python import accelerator_util
  from tensorflow.dtensor.python import layout
  from tensorflow.dtensor.python import numpy_util
  from tensorflow.dtensor.python import tpu_util
  from tensorflow.dtensor.python.tests import test_util
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.ops import math_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 2 for calling the DeviceAssignmentTest obj's underlying member method code with example usage: obj.tearDown() without return types