protected function setShortcodeAttribute($value) {
    // Extract numerics only
    $shortcode = Utilities::extractNumerics($value);
    // If shortcode doesn't begin with 29290
    if (substr($shortcode, 0, 5) != '29290') {
      // Throw error
      throw new InvalidConfig('Shortcode must start with `29290`. `' . $shortcode . '` is given');
    }
    // Set shortcode
    return $shortcode;
  }