How to use the selector.headline2 function in selector

globalSel.other = [{
            title: i18n['selector.allChildModules'],
            selector: ' .isModule'
        }, {
            title: i18n['selector.allFirstLevelChildModules'],
            // includes selector for modules with wrappers, e.g. rz_box and rz_grid
            selector: ' > .isModule, > :not(.isModule) > .isModule, > :not(.isModule) > :not(.isModule) > .isModule'
        }, {
            title: i18n['selector.headlines'],
            selector: ' h1, h2, h3, h4, h5, h6',
            items: [{
                title: i18n['selector.headline1'],
                selector: ' h1'
            },{
                title: i18n['selector.headline2'],
                selector: ' h2'
            },{
                title: i18n['selector.headline3'],
                selector: ' h3'
            },{
                title: i18n['selector.headline4'],
                selector: ' h4'
            },{
                title: i18n['selector.headline5'],
                selector: ' h5'
            },{
                title: i18n['selector.headline6'],
                selector: ' h6'
            }]
        }];