code: def test_rpc_call_op_in_tf_function(self):
      @eager_def_function.function(
          input_signature=[
              tensor_spec.TensorSpec([], dtypes.int32),
              tensor_spec.TensorSpec([], dtypes.int32),
          ]
      )
      def _remote_fn(a, b):
          return math_ops.multiply(a, b)
  
      port = portpicker.pick_unused_port()
      address = "localhost:{}".format(port)
      server_resource = rpc_ops.GrpcServer(address)
  
      server_resource.register("remote_fn", _remote_fn)
  
      server_resource.start()
      client = rpc_ops.GrpcClient(address=address, name="test_client")
  
      a = variables.Variable(2, dtype=dtypes.int32)
      b = variables.Variable(3, dtype=dtypes.int32)
  
      @eager_def_function.function
      def call_fn():
          result_or = client.call(
              args=[a, b],
              method_name="remote_fn",
              output_specs=[tensor_spec.TensorSpec([], dtypes.int32)],
          )
  
          self.assertAllEqual(True, result_or.is_ok())
          result = result_or.get_value()
          self.assertEqual(
              len(result), 1
          )  # Call returns a list(tensors)
          # TODO(ishark): Shape for output tensor is unknown currently.
          # Add attribute for capturing TensorSpec for output and enable
          # check below:
          # self.assertIsNotNone(result[0].shape.rank)
          return result
  
      self.assertAllEqual(call_fn(), [6])
  
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 12 for calling the RpcOpsTest obj's underlying member method code with example usage: obj.test_rpc_call_op_in_tf_function() and returns: math_ops, result