code: def tokenize(self, tokens: Union[str, List[str]]) -> List[str]:
      return self._tokenizer.tokenize(tokens)
  
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 3 for calling the MaskedTokenProcessor obj's underlying member method code with example usage: obj.tokenize(tokens) and returns: self