class_docstr: Customtokenizer which will tokenize the input text as words or phases and convert the words (str) to an index (int) using the vocab.
  If you would like tokens, please use `hub.BertTokenizer`.
docstr: Converts a token (str) in an id using the vocab. 
docstr_tok: ["Converts","a","token","(","str",")","in","an","id","using","the","vocab","."]
code: def _convert_token_to_id(self, token: str):
      """Converts a token (str) in an id using the vocab."""
      return self.vocab.get(token, None)
  
imports: import collections
  import inspect
  import os
  from typing import Callable, List, Union
  import paddlehub
  from paddlehub.utils.log import logger
  from paddlehub.text.bert_tokenizer import BasicTokenizer
  from paddlehub.text.utils import load_vocab, whitespace_tokenize
label_desc: Use image node_id 4 for calling the CustomTokenizer obj's underlying member method code with example usage: obj._convert_token_to_id(token) and returns: self