code: def get_rpc_layer(self):
      return "grpc"
  
imports: import time
  from tensorflow.python.distribute import multi_process_runner
  from tensorflow.python.distribute import multi_worker_test_base
  from tensorflow.python.distribute import parameter_server_strategy_v2
  from tensorflow.python.distribute.cluster_resolver import cluster_resolver
  from tensorflow.python.distribute.coordinator import cluster_coordinator
  from tensorflow.python.distribute.coordinator import metric_utils
  from tensorflow.python.eager import context
  from tensorflow.python.eager import def_function
  from tensorflow.python.eager import test
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import random_ops
  from tensorflow.python.training import coordinator
  from tensorflow.python.training.server_lib import ClusterSpec
label_desc: Use image node_id 1 for calling the MetricUtilsTest obj's underlying member method code with example usage: obj.get_rpc_layer() and returns: str