docs: function(err, res) {
          if (err) return callback(err);
          self._rawResponse = res;
          if (!res || !res['cps:reply']) return callback(new Error("Invalid reply"));
          self.seconds = res['cps:reply']['cps:seconds'];
          if (res['cps:reply']['cps:content']) {
              var content = res['cps:reply']['cps:content'];
              self = _.merge(self, content);
          }
  
          callback(res['cps:reply']['cps:error'], self);
      }