ecshop中初始化会员数据调整类的unserialize()的疑问

/**
 * 初始化会员数据整合类
 *
 * @access public
 * @return object
*/
function &init_users()
{
 $set_modules = false;
 static $cls = null;
 if ($cls != null)
 {
 return $cls;
 }
 include_once(ROOT_PATH . 'includes/modules/integrates/' . $GLOBALS['_CFG']['integrate_code'] . '.php');
 $cfg = unserialize($GLOBALS['_CFG']['integrate_config']);
 $cls = new $GLOBALS['_CFG']['integrate_code']($cfg);

 return $cls;
}