}

        @Override
        public boolean removeAll(Collection<?> c) {
          return removeEntriesIf(Maps.<K>keyPredicateOnEntries(in(c)));
        }

        @Override
        public boolean retainAll(Collection<?> c) {
          return removeEntriesIf(Maps.<K>keyPredicateOnEntries(not(in(c))));
        }

        @Override
        public boolean remove(@CheckForNull Object o) {

    }

    @Override
    protected NavigableMap<K, V1> fromMap() {
      return (NavigableMap<K, V1>) super.fromMap();
    }
  }

  static <K extends @Nullable Object> Predicate<Entry<K, ?>> keyPredicateOnEntries(
      Predicate<? super K> keyPredicate) {
    return compose(keyPredicate, Maps.<K>keyFunction());
  }

  static <V extends @Nullable Object> Predicate<Entry<?, V>> valuePredicateOnEntries(

    } else if (unfiltered instanceof FilteredMultimap) {
      FilteredMultimap<K, V> prev = (FilteredMultimap<K, V>) unfiltered;
      return filterFiltered(prev, Maps.<K>keyPredicateOnEntries(keyPredicate));
    } else {
      return new FilteredKeyMultimap<>(unfiltered, keyPredicate);
    }
  }

  /**