code: function sumsqr(values) {
        var _sumsqr = 0;
        for (var i = 0, len = values.length; i < len; i++) {
          var num = values[i];
          _sumsqr += (num * num);
        }
        return _sumsqr;
      }
docs: no need to implement rereduce=true, because Pouch will never call it