return Iterables.removeIf(
        multimap.unfiltered().entries(),
        and(multimap.entryPredicate(), valuePredicateOnEntries(in(c))));
  }

  @Override
  public boolean retainAll(Collection<?> c) {
    return Iterables.removeIf(
        multimap.unfiltered().entries(),
        and(multimap.entryPredicate(), valuePredicateOnEntries(not(in(c)))));
  }

  @Override
  public void clear() {
    multimap.clear();
  }