@Override
    public KTable<Windowed<K>, V> aggregate(final Initializer<V> initializer) {
        return aggregate(initializer, Materialized.with(null, null));
    }
@Test
    public void shouldNotHaveNullInitializerTwoOptionNamedOnAggregate() {
        assertThrows(NullPointerException.class, () ->  windowedCogroupedStream.aggregate(null, Named.as("test")));
    }