Sharepoint edit group title using JSOM

function setSomeUsers(OldTitle,newTitle) {

    var clientContext = new SP.ClientContext.get_current();

    var collGroup = clientContext.get_web().get_siteGroups();

    var oGroup = collGroup.getByName(OldTitle);

oGroup.set_title(newTitle);

    oGroup.update();

clientContext.load(oGroup );

    clientContext.executeQueryAsync(Function.createDelegate(this, this.onSetQuerySucceeded), Function.createDelegate(this, this.onQueryFailed));}

function onSetQuerySucceeded() {   

    alert(this.oGroup .get_title() + " added.");

}

function onQueryFailed(sender, args) {

    alert('Request failed. ' + args.get_message() + '\n' + args.get_stackTrace());

}