code: def _get_tokenizer(tokenizer):
      if tokenizer == "nltk":
          return nltk.word_tokenize
      return tokenizer
  
imports: import gzip
  import logging
  import os
  import shutil
  import tarfile
  import zipfile
  import nltk
  import six
  import fasttext
  import torch
  from torchtext.legacy import data, vocab
  from torchtext.utils import download_from_url
  from urllib.request import urlretrieve
label_desc: Use image node_id 2 for calling the MatchingField obj's underlying member method code with example usage: obj._get_tokenizer(tokenizer) and returns: tokenizer, nltk