class_docstr: Abstract BPE Helper.
  
  BPE Helper subclasses must implement appropriate abstractmethods.
class_docstr_tok: ["Abstract","BPE","Helper",".","BPE","Helper","subclasses","must","implement","appropriate","abstractmethods","."]
docstr: Add special tokens to the tokenizer.
  
  These tokens are never split, and prioritized over the BPE tokenization.
docstr_tok: ["Add","special","tokens","to","the","tokenizer",".","These","tokens","are","never","split",",","and","prioritized","over","the","BPE","tokenization","."]
code: def add_special_tokens(self, dict_agent, special_tokens: List[str]):
      """
      Add special tokens to the tokenizer.
  
      These tokens are never split, and prioritized over the BPE tokenization.
      """
      # note, HF ByteLevelBPE tokenizer handles special tokens itself in
      # a special way, so this will be skipped
      for token in special_tokens:
          # exploiting dictionaries' insertion ordering to emulate ordered sets
          self._special_tokens[token] = 1
  
imports: from parlai.core.params import ParlaiParser
  from abc import ABC, abstractmethod
  from functools import lru_cache
  import json
  import os
  import random
  import re
  from typing import Dict, List, Optional, Set, Tuple
  from typing_extensions import final
  from parlai.core.build_data import download, make_dir
  from parlai.core.opt import Opt
  from parlai.utils.misc import warn_once
  from parlai.utils.typing import TShared
  from parlai.utils.io import PathManager
  import parlai.utils.logging
label_desc: Use image node_id 9 for calling the BPEHelper obj's underlying member method code with example usage: obj.add_special_tokens(dict_agent, special_tokens) without return types