docs: def obj2str(obj, pk_protocol=py23.pk_protocol):
      """Convert arbitrary object to base64 encoded string.
  
      **中文文档**
  
      将可Pickle化的Python对象转化为utf-8编码的 ``纯ASCII字符串``
      """
      return base64.urlsafe_b64encode(pickle.dumps(
          obj, protocol=pk_protocol)).decode("utf-8")