code: def unregister(self, category, key):
      if _internal_kv_initialized():
          _internal_kv_del(_make_key(self.prefix, category, key))
      else:
          self._to_flush.pop((category, key), None)
  
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 5 for calling the _Registry obj's underlying member method code with example usage: obj.unregister(category, key) without return types