/**
  * @return \AGmakonts\STL\DateTime\DateTime
  */
 public function nextAnniversary() : DateTime
 {
     $nativeDate = new \DateTime($this->date()->getTimestamp()->value());
     $now = new \DateTime();
     $interval = new \DateInterval('P1Y');
     while ($nativeDate->getTimestamp() < $now->getTimestamp()) {
         $nativeDate = $nativeDate->add($interval);
     }
     return DateTime::get(Integer::get($nativeDate->getTimestamp()));
 }