public static function selectForAnswer(CMA_Answer $answer)
 {
     $ids = get_comment_meta($answer->getId(), CMA_Answer::META_ATTACHMENT, false);
     if (!empty($ids)) {
         $result = parent::select($answer->getThreadId(), get_comment_meta($answer->getId(), CMA_Answer::META_ATTACHMENT, false));
         foreach ($result as $attachment) {
             $attachment->setAnswerId($answer->getId());
         }
         return $result;
     } else {
         return array();
     }
 }