code: def _put_helper(identifier: str, obj: Any, workflow_id: str) -> None:
      # TODO (Alex): This check isn't sufficient, it only works for directly
      # nested object refs.
      if isinstance(obj, ray.ObjectRef):
          raise NotImplementedError(
              "Workflow does not support checkpointing nested object references yet."
          )
      key = _obj_id_to_key(identifier)
  
      dump_to_storage(
          key,
          obj,
          workflow_id,
          workflow_storage.WorkflowStorage(workflow_id),
          update_existing=False,
      )
  
imports: import contextlib
  from dataclasses import dataclass
  import logging
  import os
  import ray
  from ray import cloudpickle
  from ray.types import ObjectRef
  from ray.workflow import common, workflow_storage
  from typing import Any, Dict, Generator, List, Optional, Tuple, TYPE_CHECKING
  from collections import ChainMap
  import io
label_desc: Use image node_id 4 for calling a global function with example usage: _put_helper(identifier, obj, workflow_id) without return types