.factory with Firebase in Angular

FactoryFB

    .factory( 'DBService', [ '$FirebaseArray', function ($FirebaseArray) {
        var oFB_DB = new Firebase('https://<<FIREBASE-URL>>.firebaseio.com');
        return {
            getAlumnos: { function (){}
                return $firebaseArray(oFB_DB);
            }
        };
    }]);