docs: function xml2json(method, body){
    body = util.xml2json(body);
  
    if(body.return_code!=='SUCCESS'){
      throw new Error(util.format('api error to call %s: %s', method, body.return_msg));
    }
    if(body.result_code!=='SUCCESS'){
      throw new Error(util.format('business error to call %s: %s %s', method, body.err_code, body.err_code_des));
    }
    return body;
  }