private function setEventId(StringLiteral $eventId)
 {
     if ($eventId->isEmpty()) {
         throw new \InvalidArgumentException('event id can not be empty');
     }
     $this->eventId = $eventId;
 }
 /**
  * @param StringLiteral $actorId
  */
 private function setActorId(StringLiteral $actorId)
 {
     if ($actorId->isEmpty()) {
         throw new \InvalidArgumentException('actor id can not be empty');
     }
     $this->actorId = $actorId;
 }