code: private static <K, V> BiMap<K, V> filterFiltered(
        FilteredEntryBiMap<K, V> map, Predicate<? super Entry<K, V>> entryPredicate) {
      Predicate<Entry<K, V>> predicate = Predicates.and(map.predicate, entryPredicate);
      return new FilteredEntryBiMap<K, V>(map.unfiltered(), predicate);
    }
docs: Support {@code clear()}, {@code removeAll()}, and {@code retainAll()} when
  filtering a filtered map.