code: def BBoxLblBlock(
      vocab: list = None,  # Vocab labels for bounding boxes
      add_na: bool = True,  # Add NaN as a background class
  ):
      "A `TransformBlock` for labeled bounding boxes, potentially with `vocab`"
      return TransformBlock(
          type_tfms=MultiCategorize(vocab=vocab, add_na=add_na),
          item_tfms=BBoxLabeler,
      )
  
imports: from __future__ import annotations
  from ..torch_basics import *
  from ..data.all import *
  from .core import *
  import types
label_desc: Use image node_id 8 for calling a global function with example usage: BBoxLblBlock(vocab, add_na) and returns: TransformBlock