code: @CanIgnoreReturnValue
    @Override
    public Set<V> removeAll(@NullableDecl Object key) {
      return (Set<V>) super.removeAll(key);
    }
docs: {@inheritDoc}
  
  <p>Because a {@code SetMultimap} has unique values for a given key, this method returns a
  {@link Set}, instead of the {@link Collection} specified in the {@link Multimap} interface.