Concat operator - Droidcon 2016

Concatify.java

//concatify
 Observable<Student> concatify() {
    Observable<Student> slytherinObservable = getObservable(House.SLYTHERIN);
    Observable<Student> huffleObervable = getObservable(House.HUFFLEPUFF);
    Observable<Student> ravenObservable = getObservable(House.RAVENCLAW);
    Observable<Student> gryffindorObservable = getObservable(House.GRYFFINDOR);
    return Observable.concat(
            slytherinObservable,
            huffleObervable,
            ravenObservable,
            gryffindorObservable);
}