code: def flush(self):
      for k, v in self.to_flush.items():
          if isinstance(v, ray.ObjectRef):
              self.references[k] = v
          else:
              self.references[k] = ray.put(v)
      self.to_flush.clear()
  
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 4 for calling the _ParameterRegistry obj's underlying member method code with example usage: obj.flush() without return types