docs: def dump_json(token_dict, dump_path):
      """write json data to file
      """
      if sys.version > '3':
          with open(dump_path, 'w', encoding='utf-8') as output_file:
              json.dump(token_dict, output_file, indent=4)
      else:
          with open(dump_path, 'w') as output_file:
              json.dump(token_dict, output_file, indent=4)