code: function responseErrorBuilder(err, res) {
    if (res && res.body && _.isObject(res.body) && res.body.error) {
      // pass through error obj from API
      return res.body;
    } else {
      // build custom error
      return {
        error: {
          code: err.status || CL_CONSTANTS.RES_UNKNOWN,
          message: (res ? res.text : null) || err.toString(),
        }
      };
    }
  }
docs: Return an Error Object