public function get_section_info($sectionnumber, $strictness = IGNORE_MISSING) {
        if (!array_key_exists($sectionnumber, $this->sectioninfo)) {
            if ($strictness === MUST_EXIST) {
                throw new moodle_exception('sectionnotexist');
            } else {
                return null;
            }
        }
        return $this->sectioninfo[$sectionnumber];
    }