code: def __call__(self, user_message):
      greeting = f"Hello {user_message.name} from {user_message.foo}"
      num_x2 = user_message.num * 2
      user_response = serve_pb2.UserDefinedResponse(
          greeting=greeting,
          num_x2=num_x2,
      )
      return user_response
  
file_path: ray/python/ray/serve/tests/test_config_files/grpc_deployment.py
imports: from typing import Dict
  from ray import serve
  from ray.serve.generated import serve_pb2
  from ray.serve.handle import DeploymentHandle
label_desc: Use image node_id 1 for calling the GrpcDeployment obj's underlying member method code with example usage: obj.__call__(user_message) and returns: user_response