class_docstr: Constructs a Wav2Vec2 processor which wraps a Wav2Vec2 feature extractor, a Wav2Vec2 CTC tokenizer and a decoder
  with language model support into a single processor for language model boosted speech recognition decoding.
  
  Args:
      feature_extractor ([`Wav2Vec2FeatureExtractor`]):
          An instance of [`Wav2Vec2FeatureExtractor`]. The feature extractor is a required input.
      tokenizer ([`Wav2Vec2CTCTokenizer`]):
          An instance of [`Wav2Vec2CTCTokenizer`]. The tokenizer is a required input.
      decoder (`pyctcdecode.BeamSearchDecoderCTC`):
          An instance of [`pyctcdecode.BeamSearchDecoderCTC`]. The decoder is a required input.
class_docstr_tok: ["Constructs","a","Wav2Vec2","processor","which","wraps","a","Wav2Vec2","feature","extractor",",","a","Wav2Vec2","CTC","tokenizer","and","a","decoder","with","language","model","support","into","a","single","processor","for","language","model","boosted","speech","recognition","decoding",".","Args",":","feature_extractor","(","[","`","Wav2Vec2FeatureExtractor","`","]",")",":","An","instance","of","[","`","Wav2Vec2FeatureExtractor","`","]",".","The","feature","extractor","is","a","required","input",".","tokenizer","(","[","`","Wav2Vec2CTCTokenizer","`","]",")",":","An","instance","of","[","`","Wav2Vec2CTCTokenizer","`","]",".","The","tokenizer","is","a","required","input",".","decoder","(","`","pyctcdecode.BeamSearchDecoderCTC","`",")",":","An","instance","of","[","`","pyctcdecode.BeamSearchDecoderCTC","`","]",".","The","decoder","is","a","required","input","."]
code: def get_missing_alphabet_tokens(decoder, tokenizer):
      from pyctcdecode.alphabet import (
          BLANK_TOKEN_PTN,
          UNK_TOKEN,
          UNK_TOKEN_PTN,
      )
  
      # we need to make sure that all of the tokenizer's except the special tokens
      # are present in the decoder's alphabet. Retrieve missing alphabet token
      # from decoder
      tokenizer_vocab_list = list(tokenizer.get_vocab().keys())
  
      # replace special tokens
      for i, token in enumerate(tokenizer_vocab_list):
          if BLANK_TOKEN_PTN.match(token):
              tokenizer_vocab_list[i] = ""
          if token == tokenizer.word_delimiter_token:
              tokenizer_vocab_list[i] = " "
          if UNK_TOKEN_PTN.match(token):
              tokenizer_vocab_list[i] = UNK_TOKEN
  
      # are any of the extra tokens no special tokenizer tokens?
      missing_tokens = set(tokenizer_vocab_list) - set(
          decoder._alphabet.labels
      )
  
      return missing_tokens
  
imports: import os
  import warnings
  from contextlib import contextmanager, nullcontext
  from dataclasses import dataclass
  from multiprocessing import Pool, get_context, get_start_method
  from typing import TYPE_CHECKING, Dict, Iterable, List, Optional, Union
  import numpy
  from ...processing_utils import ProcessorMixin
  from ...utils import ModelOutput, logging, requires_backends
label_desc: Use image node_id 6 for calling the Wav2Vec2ProcessorWithLM obj's underlying member method code with example usage: obj.get_missing_alphabet_tokens(decoder, tokenizer) and returns: missing_tokens