* @return {@code dest}
   */
  @CanIgnoreReturnValue
  public static <K extends @Nullable Object, V extends @Nullable Object, M extends Multimap<K, V>>
      M invertFrom(Multimap<? extends V, ? extends K> source, M dest) {
    checkNotNull(dest);
    for (Map.Entry<? extends V, ? extends K> entry : source.entries()) {
      dest.put(entry.getValue(), entry.getKey());
    }