public static <T> Observable<T> merge(Single<? extends T> t1, Single<? extends T> t2, Single<? extends T> t3, Single<? extends T> t4, Single<? extends T> t5, Single<? extends T> t6, Single<? extends T> t7) {
        return Observable.merge(asObservable(t1), asObservable(t2), asObservable(t3), asObservable(t4), asObservable(t5), asObservable(t6), asObservable(t7));
    }