code: def test_ngrams_tokenize(n, separator, expected_values):
      strings = cudf.Series(
          ["this is my favorite", "book on my bookshelf"]
      )
  
      expected = cudf.Series(expected_values)
  
      actual = strings.str.ngrams_tokenize(n=n, separator=separator)
  
      assert type(expected) == type(actual)
      assert_eq(expected, actual)
  
imports: import random
  import string
  import numpy
  import pytest
  import cudf
  from cudf.core.byte_pair_encoding import BytePairEncoder
  from cudf.core.tokenize_vocabulary import TokenizeVocabulary
  from cudf.testing._utils import assert_eq
label_desc: Use image node_id 11 for calling a global function with example usage: test_ngrams_tokenize(n, separator, expected_values) without return types