code: def test_special_tokens_mask(self):
      tokenizers = self.get_tokenizers(do_lower_case=False)
      for tokenizer in tokenizers:
          with self.subTest(f"{tokenizer.__class__.__name__}"):
              nodes, xpaths = self.get_nodes_and_xpaths()
              # Testing single inputs
              encoded_sequence = tokenizer.encode(
                  nodes, xpaths=xpaths, add_special_tokens=False
              )
              encoded_sequence_dict = tokenizer.encode_plus(
                  nodes,
                  xpaths=xpaths,
                  add_special_tokens=True,
                  return_special_tokens_mask=True,
              )
              encoded_sequence_w_special = encoded_sequence_dict[
                  "input_ids"
              ]
              special_tokens_mask = encoded_sequence_dict[
                  "special_tokens_mask"
              ]
              self.assertEqual(
                  len(special_tokens_mask),
                  len(encoded_sequence_w_special),
              )
  
              filtered_sequence = [
                  x
                  for i, x in enumerate(encoded_sequence_w_special)
                  if not special_tokens_mask[i]
              ]
              self.assertEqual(encoded_sequence, filtered_sequence)
  
imports: import inspect
  import json
  import os
  import re
  import shutil
  import tempfile
  import unittest
  from typing import List
  from transformers import AddedToken, MarkupLMTokenizerFast, SpecialTokensMixin, is_tf_available, is_torch_available, logging
  from transformers.models.markuplm.tokenization_markuplm import VOCAB_FILES_NAMES, MarkupLMTokenizer
  from transformers.testing_utils import is_pt_tf_cross_test, require_tokenizers, require_torch, slow
  from ...test_tokenization_common import SMALL_TRAINING_CORPUS, TokenizerTesterMixin, merge_model_tokenizer_mappings
label_desc: Use image node_id 25 for calling the MarkupLMTokenizationTest obj's underlying member method code with example usage: obj.test_special_tokens_mask() without return types