code: def test_issue4190():
      def customize_tokenizer(nlp):
          prefix_re = compile_prefix_regex(nlp.Defaults.prefixes)
          suffix_re = compile_suffix_regex(nlp.Defaults.suffixes)
          infix_re = compile_infix_regex(nlp.Defaults.infixes)
          # Remove all exceptions where a single letter is followed by a period (e.g. 'h.')
          exceptions = {
              k: v
              for k, v in dict(
                  nlp.Defaults.tokenizer_exceptions
              ).items()
              if not (len(k) == 2 and k[1] == ".")
          }
          new_tokenizer = Tokenizer(
              nlp.vocab,
              exceptions,
              prefix_search=prefix_re.search,
              suffix_search=suffix_re.search,
              infix_finditer=infix_re.finditer,
              token_match=nlp.tokenizer.token_match,
              faster_heuristics=False,
          )
          nlp.tokenizer = new_tokenizer
  
      test_string = "Test c."
      # Load default language
      nlp_1 = English()
      doc_1a = nlp_1(test_string)
      result_1a = [token.text for token in doc_1a]  # noqa: F841
      # Modify tokenizer
      customize_tokenizer(nlp_1)
      doc_1b = nlp_1(test_string)
      result_1b = [token.text for token in doc_1b]
      # Save and Reload
      with make_tempdir() as model_dir:
          nlp_1.to_disk(model_dir)
          nlp_2 = load_model(model_dir)
      # This should be the modified tokenizer
      doc_2 = nlp_2(test_string)
      result_2 = [token.text for token in doc_2]
      assert result_1b == result_2
      assert nlp_2.tokenizer.faster_heuristics is False
  
file_path: spaCy/spacy/tests/serialize/test_serialize_tokenizer.py
imports: import pickle
  import re
  import pytest
  from spacy.attrs import ENT_IOB, ENT_TYPE
  from spacy.lang.en import English
  from spacy.tokenizer import Tokenizer
  from spacy.tokens import Doc
  from spacy.util import compile_infix_regex, compile_prefix_regex, compile_suffix_regex, get_lang_class, load_model
  from ..util import assert_packed_msg_equal, make_tempdir
label_desc: Use image node_id 4 for calling a global function with example usage: test_issue4190() without return types