public function getUsers($descendants = false) {
    if ($descendants) {
      $groups = $this->getDescendants();
      $or = ['|',
          'ref' => [
            ['group', $groups],
            ['groups', $groups]
          ]
        ];
    } else {
      $or = null;
    }
    $groups[] = $this;
    $return = Nymph::getEntities(
        ['class' => '\Tilmeld\Entities\User'],
        ['&',
          'equal' => ['enabled', true]
        ],
        $or
    );
    return $return;
  }