code: def get_vocab_size(self) -> int:
      return len(self._tokenizer)
  
imports: import copy
  import random
  from typing import Any, Dict, List, Optional, Tuple, Union
  import torch
  from mmf.common.registry import registry
  from mmf.common.sample import Sample, SampleList
  from mmf.datasets.processors.processors import BaseProcessor
label_desc: Use image node_id 2 for calling the MaskedTokenProcessor obj's underlying member method code with example usage: obj.get_vocab_size() and returns: len