code: def _log_post_backward_hook(
      state: _FSDPState, handle: "FlatParamHandle", log: logging.Logger
  ) -> None:
      # Under TORCH_DISTRIBUTED_DEBUG=INFO, log the module names this hook fires for.
      # Below logging of module names this post-bwd hook fires for can help debug certain
      # cases where hooks don't fire, such as under certain activation checkpoint configs.
      if (
          state._use_orig_params
          and handle._debug_level == dist.DebugLevel.INFO
      ):
          param_fqns = _get_handle_fqns_from_root(state, handle)
          log.warning(
              "FSDP firing post-backward hooks for parameters %s",
              param_fqns,
          )
  
imports: import logging
  import traceback
  import warnings
  import weakref
  from enum import auto, Enum
  from functools import partial
  from typing import Any, Callable, cast, Dict, Generator, Iterable, List, no_type_check, Optional, Set, Tuple, Type, TYPE_CHECKING
  import torch
  import torch.distributed
  import torch.distributed.fsdp._flat_param
  import torch.nn
  from torch.distributed._composable_state import _get_module_state, _State
  from torch.distributed._tensor.device_mesh import DeviceMesh
  from torch.distributed.algorithms._checkpoint.checkpoint_wrapper import _CHECKPOINT_PREFIX
  from torch.distributed.fsdp._fsdp_extensions import FSDPExtensions
  from torch.distributed.utils import _apply_to_tensors
  from torch.utils._mode_utils import no_dispatch
  from .api import FullOptimStateDictConfig, FullStateDictConfig, OptimStateDictConfig, ShardingStrategy, StateDictConfig, StateDictType
label_desc: Use image node_id 12 for calling a global function with example usage: _log_post_backward_hook(state, handle, log) without return types