docs: function (to, callback, param) {
              _gpfObjectForEach(this._members, function (attributeArray, member) {
                  member = _gpfDecodeAttributeMember(member);
                  attributeArray._array.forEach(function (attribute) {
                      if (!callback || callback(member, attribute, param)) {
                          to.add(member, attribute);
                      }
                  });
              });
              return to;
          }