public static function update_definitions($coreonly = false) {
        global $CFG;
        // Include locallib.
        require_once($CFG->dirroot.'/cache/locallib.php');
        // First update definitions
        cache_config_writer::update_definitions($coreonly);
        // Second reset anything we have already initialised to ensure we're all up to date.
        cache_factory::reset();
    }