code: def bart_tokenizer(self) -> BartTokenizer:
      return BartTokenizer.from_pretrained(
          os.path.join(self.tmpdirname, "bart_tokenizer")
      )
  
imports: import json
  import os
  import shutil
  import tempfile
  import unittest
  from unittest.mock import patch
  import numpy
  from transformers import BartTokenizer
  from transformers.models.bert.tokenization_bert import VOCAB_FILES_NAMES
  from transformers.models.dpr.tokenization_dpr import DPRQuestionEncoderTokenizer
  from transformers.models.roberta.tokenization_roberta import VOCAB_FILES_NAMES
  from transformers.testing_utils import require_sentencepiece, require_tf, require_tokenizers, slow
  from transformers.utils import cached_property, is_datasets_available, is_faiss_available, is_tf_available
  from ..bart.test_modeling_tf_bart import TFBartModelTester
  from ..dpr.test_modeling_tf_dpr import TFDPRModelTester
label_desc: Use image node_id 3 for calling the TFRagTestMixin obj's underlying member method code with example usage: obj.bart_tokenizer() and returns: BartTokenizer