public static function autoload($class)
    {
        /**
         * Classes from unified namespace canot be loaded by this auto loader.
         * Do not try to load them in order to avoid strange errors in edge cases.
         */
        if (false !== strpos($class, 'OxidEsales\Eshop\\')) {
            return false;
        }
        $instance = static::getInstance();

        $class = strtolower(basename($class));

        if ($classPath = $instance->getFilePath($class)) {
            include $classPath;
        } else {
            $class = preg_replace('/_parent$/i', '', $class);

            if (!in_array($class, $instance->triedClasses)) {
                $instance->triedClasses[] = $class;
                $instance->createExtensionClassChain($class);
            }
        }
    }