* documentation for {@link Collection}:
   *
   * <blockquote>
   *
   * "Some collection implementations have restrictions on the elements that they may contain. For
   * example, some implementations prohibit null elements, and some have restrictions on the types
   * of their elements."
   *
   * </blockquote>
   */
  RESTRICTS_ELEMENTS,

  /**

  public static <K extends Comparable<?>, V> Builder<K, V> builder() {
    return new Builder<>();
  }

  /**
   * A builder for immutable range maps. Overlapping ranges are prohibited.
   *
   * @since 14.0
   */
  @DoNotMock
  public static final class Builder<K extends Comparable<?>, V> {
    private final List<Entry<Range<K>, V>> entries;

    public Builder() {