class_docstr: Test for SlowBytelevelBPE.
  
  Essentially, test whether using a stand-in GPT2 tokenizer for a dict originally
  built with HF's tokenizer produces the same results.
class_docstr_tok: ["Test","for","SlowBytelevelBPE",".","Essentially",",","test","whether","using","a","stand-in","GPT2","tokenizer","for","a","dict","originally","built","with","HF","'s","tokenizer","produces","the","same","results","."]
code: def test_gpt2standin(self):
      with testing_utils.tempdir() as tmpdir:
          # we need to build the dict file
          hf_bpe_opt = self._get_dict_opt("bytelevelbpe")
          slow_bytelevel_bpe_opt = self._get_dict_opt(
              "slow_bytelevel_bpe"
          )
  
          dict_file = os.path.join(tmpdir, "dict")
          pp = build_dict.setup_args()
          pp.set_defaults(**hf_bpe_opt)
          pp.set_defaults(task="babi")
          popt = pp.parse_args([])
          popt["dict_file"] = dict_file
          build_dict.build_dict(popt)
  
          hf_bpe_opt["dict_file"] = dict_file
          hf_bpe = DictionaryAgent(hf_bpe_opt)
  
          slow_bytelevel_bpe_opt["dict_file"] = dict_file
          slow_bytelevel_bpe = DictionaryAgent(slow_bytelevel_bpe_opt)
  
          self._run_test(slow_bytelevel_bpe, hf_bpe)
  
          slow_bytelevel_bpe_opt["bpe_add_prefix_space"] = True
          slow_bytelevel_bpe = DictionaryAgent(slow_bytelevel_bpe_opt)
          self._run_prefix_space_test(slow_bytelevel_bpe)
  
imports: from parlai.core.build_data import modelzoo_path
  from parlai.core.dict import find_ngrams
  from parlai.core.params import ParlaiParser
  from parlai.core.dict import DictionaryAgent, TokenizationMode
  from parlai.core.opt import Opt
  import parlai.scripts.build_dict
  from parlai.utils.io import PathManager
  import parlai.utils.testing
  import os
  import shutil
  import unittest
  import pytest
label_desc: Use image node_id 3 for calling the TestGpt2HFInterop obj's underlying member method code with example usage: obj.test_gpt2standin() without return types