public function commentAsUser(?Model $user, string $comment)
    {
        $commentClass = config('comments.comment_class');

        $comment = new $commentClass([
            'comment' => $comment,
            'is_approved' => ($user instanceof Commentator) ? ! $user->needsCommentApproval($this) : false,
            'user_id' => is_null($user) ? null : $user->getKey(),
            'commentable_id' => $this->getKey(),
            'commentable_type' => get_class(),
        ]);

        return $this->comments()->save($comment);
    }