code: def test_batch_tokenize(self):
      token_list = self.tok.batch_tokenize(["a b c", "d e f"])
      self.assertListEqual(
          token_list, [["a", "b", "c"], ["d", "e", "f"]]
      )
  
imports: import unittest
  from collections import defaultdict
  import numpy
  import numpy.testing
  from cornac.data import TextModality, ReviewModality
  from cornac.data.text import SPECIAL_TOKENS, DEFAULT_PRE_RULES, BaseTokenizer, Vocabulary, CountVectorizer, TfidfVectorizer
label_desc: Use image node_id 4 for calling the TestBaseTokenizer obj's underlying member method code with example usage: obj.test_batch_tokenize() without return types