* previously configured separator between each.
   */
  public final String join(Iterable<? extends @Nullable Object> parts) {
    return join(parts.iterator());
  }

  /**
   * Returns a string containing the string representation of each of {@code parts}, using the
   * previously configured separator between each.
   *
   * @since 11.0
   */

   * previously configured separator between each.
   */
  public final String join(Iterable<? extends @Nullable Object> parts) {
    return join(parts.iterator());
  }

  /**
   * Returns a string containing the string representation of each of {@code parts}, using the
   * previously configured separator between each.
   *
   * @since 11.0
   */