return new FilteredKeySetMultimap<>(
          prev.unfiltered(), Predicates.<K>and(prev.keyPredicate, keyPredicate));
    } else if (unfiltered instanceof FilteredSetMultimap) {
      FilteredSetMultimap<K, V> prev = (FilteredSetMultimap<K, V>) unfiltered;
      return filterFiltered(prev, Maps.<K>keyPredicateOnEntries(keyPredicate));
    } else {
      return new FilteredKeySetMultimap<>(unfiltered, keyPredicate);