code: def test_form_ngrams():
      sequence = (
          "Hello my name is Bob, I like eating pizza, chicken, chips and ice cream. Maybe I should eat some"
          " more salad but it's so booooring. I just... like eating pizza, chicken, chips and ice cream so much."
      )
  
      n_values = [1, 2, 3, 5, 13]
      for n in n_values:
          comparison = simple_ngram(sequence, n)
          result_to_test = list(form_ngrams(iter(sequence), n))
          assert len(comparison) == len(result_to_test)
          assert comparison == result_to_test
  
file_path: lm-evaluation-harness/tests/test_janitor.py
imports: import re
  from collections import defaultdict
  from lm_eval.decontamination.janitor import Janitor, form_ngrams, word_ngrams, split_indices, word_ngrams_indices
label_desc: Use image node_id 2 for calling a global function with example usage: test_form_ngrams() without return types