code: def test_gpt2_bpe_tokenizer(self):
      tokenizer = GPT2BPETokenizer.from_config(
          GPT2BPETokenizer.Config(
              bpe_vocab_path="pytext/data/test/data/gpt2_vocab.bpe",
              bpe_encoder_path="pytext/data/test/data/gpt2_encoder.json",
          )
      )
      text_list = ["Prototype", " Prototype"]
      expected_list = [
          [Token("19703", 0, 4), Token("8690", 4, 9)],
          [
              Token("220", 0, 0),
              Token("19703", 1, 5),
              Token("8690", 5, 10),
          ],
      ]
  
      for text, expected in zip(text_list, expected_list):
          tokens = tokenizer.tokenize(text)
          self.assertEqual(tokens, expected)
  
imports: import unittest
  from pytext.data.tokenizers import GPT2BPETokenizer, SentencePieceTokenizer, SPEandWordTokenizer, Tokenizer, WordPieceTokenizer
  from pytext.data.tokenizers.tokenizer import Token
label_desc: Use image node_id 1 for calling the GPT2BPETest obj's underlying member method code with example usage: obj.test_gpt2_bpe_tokenizer() without return types