}
  }

  /**
   * Constructs an {@code ImmutableSortedSet} from the first {@code n} elements of {@code contents}.
   * If {@code k} is the size of the returned {@code ImmutableSortedSet}, then the sorted unique
   * elements are in the first {@code k} positions of {@code contents}, and {@code contents[i] ==
   * null} for {@code k <= i < n}.
   *

   *
   * @param set the set of elements to construct a power set from
   * @return the power set, as an immutable set of immutable sets
   * @throws IllegalArgumentException if {@code set} has more than 30 unique elements (causing the
   *     power set size to exceed the {@code int} range)
   * @throws NullPointerException if {@code set} is or contains {@code null}

  }

  /**
   * Constructs an {@code ImmutableSet} from the first {@code n} elements of the specified array. If
   * {@code k} is the size of the returned {@code ImmutableSet}, then the unique elements of {@code
   * elements} will be in the first {@code k} positions, and {@code elements[i] == null} for {@code
   * k <= i < n}.
   *