}

  /**
   * Creates a <i>mutable</i>, empty {@code TreeMap} instance using the natural ordering of its
   * elements.
   *
   * <p><b>Note:</b> if mutability is not required, use {@link ImmutableSortedMap#of()} instead.
   *
   * <p><b>Note:</b> this method is now unnecessary and should be treated as deprecated. Instead,
   * use the {@code TreeMap} constructor directly, taking advantage of <a