code: def test_get_word_ngrams():
      sentences = PlaintextParser.from_string(
          "This is a test.", Tokenizer("english")
      ).document.sentences
      expected_ngrams = {("This", "is"), ("is", "a"), ("a", "test")}
      found_ngrams = _get_word_ngrams(2, sentences)
  
      assert expected_ngrams == found_ngrams
  
file_path: sumy/tests/test_evaluation/test_evaluation_rouge.py
imports: from __future__ import absolute_import
  from __future__ import division, print_function, unicode_literals
  from pytest import approx
  from sumy.evaluation import rouge_n, rouge_l_sentence_level, rouge_l_summary_level
  from sumy.evaluation.rouge import _get_ngrams, _split_into_words, _get_word_ngrams, _len_lcs, _recon_lcs, _union_lcs
  from sumy.nlp.tokenizers import Tokenizer
  from sumy.parsers.plaintext import PlaintextParser
label_desc: Use image node_id 3 for calling a global function with example usage: test_get_word_ngrams() without return types