code: def test_tensor_type_from_str(self):
      self.assertEqual(TensorType("tf"), TensorType.TENSORFLOW)
      self.assertEqual(TensorType("pt"), TensorType.PYTORCH)
      self.assertEqual(TensorType("np"), TensorType.NUMPY)
  
imports: import os
  import pickle
  import tempfile
  import unittest
  from typing import Callable, Optional
  import numpy
  from transformers import PreTrainedTokenizerFast
  from transformers import BatchEncoding, BertTokenizer, BertTokenizerFast, PreTrainedTokenizer, TensorType, TokenSpan, is_tokenizers_available
  from transformers.models.gpt2.tokenization_gpt2 import GPT2Tokenizer
  from transformers.testing_utils import CaptureStderr, require_flax, require_tf, require_tokenizers, require_torch, slow
label_desc: Use image node_id 4 for calling the TokenizerUtilsTest obj's underlying member method code with example usage: obj.test_tensor_type_from_str() without return types