@Override
    public <VR> KTable<K, VR> aggregate(final Initializer<VR> initializer,
                                        final Aggregator<? super K, ? super V, VR> aggregator,
                                        final Materialized<K, VR, KeyValueStore<Bytes, byte[]>> materialized) {
        return aggregate(initializer, aggregator, NamedInternal.empty(), materialized);
    }
@Test
    public void shouldNotHaveNullAdderOnAggregate() {
        assertThrows(NullPointerException.class, () ->  groupedStream.aggregate(MockInitializer.STRING_INIT, null, Materialized.as("store")));
    }