@CheckReturnValue
    @NonNull
    @SchedulerSupport(SchedulerSupport.NONE)
    public static <T> Observable<T> amb(Iterable<? extends ObservableSource<? extends T>> sources) {
        ObjectHelper.requireNonNull(sources, "sources is null");
        return RxJavaPlugins.onAssembly(new ObservableAmb<T>(null, sources));
    }