/**
   * Returns a serializable ordering that uses the natural order of the values. The ordering throws
   * a {@link NullPointerException} when passed a null parameter.
   *
   * <p>The type specification is {@code <C extends Comparable>}, instead of the technically correct
   * {@code <C extends Comparable<? super C>>}, to support legacy types from before Java 5.
   *

 * equals</i>. That is, {@code a.compareTo(b)} or {@code comparator.compare(a, b)} should equal zero
 * <i>if and only if</i> {@code a.equals(b)}. If this advice is not followed, the resulting
 * collection will not correctly obey its specification.
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/ImmutableCollectionsExplained">immutable collections</a>.
 *
 * @author Louis Wasserman
 * @since 12.0
 */

 * equals</i>. That is, {@code a.compareTo(b)} or {@code comparator.compare(a, b)} should equal zero
 * <i>if and only if</i> {@code a.equals(b)}. If this advice is not followed, the resulting
 * collection will not correctly obey its specification.
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/ImmutableCollectionsExplained">immutable collections</a>.
 *
 * @author Louis Wasserman
 * @since 12.0
 */