code: def testPhysicalDevices(self):
      cpus = config.list_physical_devices("CPU")
      self.assertGreater(len(cpus), 0)
      if test_util.is_gpu_available():
          gpus = config.list_physical_devices("GPU")
          self.assertGreater(len(gpus), 0)
  
imports: from absl.testing import parameterized
  from tensorflow.core.protobuf import cluster_pb2
  from tensorflow.core.protobuf import config_pb2
  from tensorflow.core.protobuf import rewriter_config_pb2
  from tensorflow.core.protobuf import tensorflow_server_pb2
  from tensorflow.python.eager import context
  from tensorflow.python.eager import def_function
  from tensorflow.python.framework import config
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import errors
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import test_ops
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import math_ops
  from tensorflow.python.platform import test
  from tensorflow.python.util import compat
label_desc: Use image node_id 1 for calling the DeviceTest obj's underlying member method code with example usage: obj.testPhysicalDevices() without return types