code: def test_tokenize(self):
      tokens = self.tok.tokenize("a b c")
      self.assertListEqual(tokens, ["a", "b", "c"])
  
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 3 for calling the TestBaseTokenizer obj's underlying member method code with example usage: obj.test_tokenize() without return types