public static function sensei_delete_quiz_answers($quiz_id = 0, $user_id = 0)
 {
     if (intval($user_id) == 0) {
         $user_id = get_current_user_id();
     }
     $delete_answers = false;
     if (intval($quiz_id) > 0) {
         $questions = WooThemes_Sensei_Utils::sensei_get_quiz_questions($quiz_id);
         foreach ($questions as $question) {
             $delete_answers = WooThemes_Sensei_Utils::sensei_delete_activities(array('post_id' => $question->ID, 'user_id' => $user_id, 'type' => 'sensei_user_answer'));
         }
     }
     return $delete_answers;
 }