code: def prefix(self):
      if not self._prefix:
          self._prefix = ray.get_runtime_context().get_job_id()
      return self._prefix
  
imports: import atexit
  import logging
  from functools import partial
  from types import FunctionType
  from typing import Callable, Optional, Type, Union
  import ray
  import ray.cloudpickle
  from ray.experimental.internal_kv import _internal_kv_get, _internal_kv_initialized, _internal_kv_put, _internal_kv_del
  from ray.tune.error import TuneError
  from ray.util.annotations import DeveloperAPI
label_desc: Use image node_id 2 for calling the _Registry obj's underlying member method code with example usage: obj.prefix() and returns: self