code: def test_stopwords(self):
      text = "this is a nice house"
  
      tok = BaseTokenizer(stop_words="english")
      self.assertListEqual(tok.tokenize(text), ["nice", "house"])
  
      tok = BaseTokenizer(stop_words=["is", "a"])
      self.assertListEqual(
          tok.tokenize(text), ["this", "nice", "house"]
      )
  
      try:
          BaseTokenizer(stop_words="vietnamese")
      except ValueError:
          assert True
  
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 6 for calling the TestBaseTokenizer obj's underlying member method code with example usage: obj.test_stopwords() without return types