class_docstr: Original BERT wordpiece tokenizer.
code: def inv_vocab(self):
      return self.tokenizer.inv_vocab
  
imports: from abc import ABC, abstractmethod
  from colossalai.legacy.context import ParallelMode
  from colossalai.legacy.core import global_context
  from .bert_tokenization import FullTokenizer
label_desc: Use image node_id 6 for calling the _BertWordPieceTokenizer obj's underlying member method code with example usage: obj.inv_vocab() and returns: self