ImmutableList.<K>asImmutableList(sortedKeys), comparator),
              ImmutableList.<V>asImmutableList(sortedValues));
      }
    }

    /**
     * Throws UnsupportedOperationException. A future version may support this operation. Then the
     * value for any given key will be the one that was last supplied in a {@code put} operation for
     * that key.
     *
     * @throws UnsupportedOperationException always