code: public static <C extends Comparable<?>> Range<C> downTo(C endpoint, BoundType boundType) {
      switch (boundType) {
        case OPEN:
          return greaterThan(endpoint);
        case CLOSED:
          return atLeast(endpoint);
        default:
          throw new AssertionError();
      }
    }
docs: Returns a range from the given endpoint, which may be either inclusive (closed) or exclusive
  (open), with no upper bound.
  
  @since 14.0