code: def test_multi_device_resource_cpu(self):
      with ops.device("/device:cpu:1"):
          v = variables.Variable(initial_value=0, dtype=dtypes.int64)
  
      @eager_def_function.function(
          input_signature=[tensor_spec.TensorSpec([], dtypes.int64)]
      )
      def assign_add(a):
          v.assign_add(a)
  
      with ops.device("/device:CPU:0"):
          port = portpicker.pick_unused_port()
          address = "localhost:{}".format(port)
          server = rpc_ops.GrpcServer(address)
          server.register("assign_add", assign_add)
          server.start()
  
          client = rpc_ops.GrpcClient(
              address, list_registered_methods=True
          )
          result_or = client.assign_add(
              variables.Variable(2, dtype=dtypes.int64)
          )
          self.assertAllEqual(result_or.is_ok(), True)
  
      self.assertAllEqual(v, 2)
  
imports: import threading
  import time
  import numpy
  import portpicker
  from tensorflow.python.distribute.experimental.rpc import rpc_ops
  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 tensor_spec
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import data_flow_ops
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import resource_variable_ops
  from tensorflow.python.ops import variables
  from tensorflow.python.platform import test
  from tensorflow.python.util import nest
label_desc: Use image node_id 20 for calling the RpcOpsTest obj's underlying member method code with example usage: obj.test_multi_device_resource_cpu() without return types