code: def test_normalize_words():
      summarizer = _build_summarizer(EMPTY_STOP_WORDS)
      sentence = "This iS A test 2 CHECk normalization."
      words_original = sentence.split()
      words_normalized = summarizer._normalize_words(words_original)
  
      words_correctly_normalized = (
          "this is a test 2 check normalization.".split()
      )
      assert words_normalized == words_correctly_normalized
  
file_path: sumy/tests/test_summarizers/test_sum_basic.py
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import pytest
  from sumy.models.dom._sentence import Sentence
  from sumy.nlp.tokenizers import Tokenizer
  from sumy.summarizers.sum_basic import SumBasicSummarizer
  from sumy.nlp.stemmers import Stemmer
  from ..utils import build_document
label_desc: Use image node_id 5 for calling a global function with example usage: test_normalize_words() without return types