public function import_hints($qo, $questionxml, $withparts = false,
            $withoptions = false, $defaultformat = 'html') {
        if (!isset($questionxml['#']['hint'])) {
            return;
        }

        foreach ($questionxml['#']['hint'] as $hintxml) {
            $hint = $this->import_hint($hintxml, $defaultformat);
            $qo->hint[] = $hint->hint;

            if ($withparts) {
                $qo->hintshownumcorrect[] = $hint->shownumcorrect;
                $qo->hintclearwrong[] = $hint->clearwrong;
            }

            if ($withoptions) {
                $qo->hintoptions[] = $hint->options;
            }
        }
    }