*/
    @CanIgnoreReturnValue
    public Builder<E> addCopies(E element, int occurrences) {
      requireNonNull(contents); // see the comment on the field
      if (occurrences == 0) {
        return this;
      }
      if (buildInvoked) {
        contents = new ObjectCountHashMap<E>(contents);
        isLinkedHash = false;
      }

     *     might be the keys' natural order)
     * @since 31.0
     */
    @Override
    @SuppressWarnings("unchecked") // see inline comments
    public ImmutableSortedMap<K, V> buildOrThrow() {
      switch (size) {
        case 0:
          return emptyMap(comparator);
        case 1:
          // We're careful to put only K and V instances in.