code: def __call__(self) -> str:
      return "Hi from Serve deployment"
  
file_path: ray/doc/source/serve/doc_code/model_composition/response_to_object_ref_example.py
imports: import ray
  from ray import serve
  from ray.serve.handle import DeploymentHandle, DeploymentResponse
label_desc: Use image node_id 1 for calling the SayHi obj's underlying member method code with example usage: obj.__call__() and returns: str