class_docstr: BPE Helper for GPT2 Models.
  
  Original source:
      https://github.com/openai/gpt-2/blob/main/src/encoder.py
  
  Original license: MIT
  
  This is a modified implementation from that of fairseq:
      https://github.com/pytorch/fairseq/blob/main/fairseq/data/encoders/gpt2_bpe_utils.py
  
  Fairseq license: MIT
class_docstr_tok: ["BPE","Helper","for","GPT2","Models",".","Original","source",":","https",":","\/\/github.com\/openai\/gpt-2\/blob\/main\/src\/encoder.py","Original","license",":","MIT","This","is","a","modified","implementation","from","that","of","fairseq",":","https",":","\/\/github.com\/pytorch\/fairseq\/blob\/main\/fairseq\/data\/encoders\/gpt2_bpe_utils.py","Fairseq","license",":","MIT"]
docstr: Tokenize text.
  
  :param text:
      text to tokenize
  
  :return tokens:
      A list of tokens
docstr_tok: ["Tokenize","text",".",":","param","text",":","text","to","tokenize",":","return","tokens",":","A","list","of","tokens"]
code: def helper_encode(self, text: str) -> List[str]:
      """
      Tokenize text.
  
      :param text:
          text to tokenize
  
      :return tokens:
          A list of tokens
      """
      bpe_tokens: List[str] = []
      for token in regex.findall(self.pat, text):
          token = "".join(
              self.byte_encoder[b] for b in token.encode("utf-8")
          )
          bpe_tokens.extend(
              self.encoder[bpe_token]
              for bpe_token in self.bpe(token).split(" ")
          )
      return bpe_tokens
  
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 8 for calling the Gpt2BpeHelper obj's underlying member method code with example usage: obj.helper_encode(text) and returns: bpe_tokens