docs: function (member, memberValue, visibility) {
          if (undefined === visibility) {
              visibility = _GPF_VISIBILITY_PUBLIC;
          } else {
              visibility = _gpfVisibilityKeywords.indexOf(visibility);
              if (-1 === visibility) {
                  gpf.Error.classInvalidVisibility();
              }
          }
          this._addMember(member, memberValue, visibility);
      }