public function serialize($quiz, $questions)
{
$writer = new ImsQtiWriter();
$quiz_id = self::get_identifier($quiz);
$test = $writer->add_assessmentTest($quiz_id, $quiz->name, self::get_tool_name(), Qti::get_tool_version());
$part = $test->add_testPart(null, Qti::NAVIGATION_MODE_LINEAR, Qti::SUBMISSION_MODE_INDIVIDUAL);
$part->add_itemSessionControl(0, true, true, true, true, true, false);
$section = $part->add_assessmentSection(null, $quiz->name, false);
$instruction = $this->translate_question_text($quiz->intro);
$section->add_rubricBlock(Qti::VIEW_ALL)->add_flow($instruction);
$this->add_questions($section, $quiz, $questions);
return $writer->saveXML();
}
