public function getDescendants($andSelf = false) {
    $return = [];
    $entities = Nymph::getEntities(
        ['class' => '\Tilmeld\Entities\Group'],
        ['&',
          'equal' => ['enabled', true],
          'ref' => ['parent', $this]
        ]
    );
    foreach ($entities as $entity) {
      $childArray = $entity->getDescendants(true);
      $return = array_merge($return, $childArray);
    }
    $hooked = $this;
    if (class_exists('\SciActive\Hook')) {
      $class = get_class();
      \SciActive\Hook::hookObject($hooked, $class.'->', false);
    }
    if ($andSelf) {
      $return[] = $hooked;
    }
    return $return;
  }