code: def test_build_bpe(self):
      self._run_test({"dict_tokenizer": "bpe", "max_tokens": 50})
  
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 4 for calling the TestBuildDict obj's underlying member method code with example usage: obj.test_build_bpe() without return types