public function create(Dto $commentDto) : Dto
 {
     /** @var Comment $comment */
     $comment = $this->dtoToEntityMapper->transform($commentDto);
     $this->commentRepository->add($comment);
     $this->systemWideEventDispatcher->dispatch(new CommentHasBeenAdded($comment->getAuthorsUsername(), $comment->getPostId()));
     foreach ($comment->getMentions() as $mention) {
         $this->systemWideEventDispatcher->dispatch(new UserHasBeenMentioned($comment->getAuthorsUsername(), $mention->getUsername(), $comment->getPostId()));
     }
     return $this->entityToDtoMapper->transform($comment);
 }