private static function getOrderedClasses(array $classes)
    {
        $map = array();
        self::$seen = array();
        foreach ($classes as $class) {
            try {
                $reflectionClass = new \ReflectionClass($class);
            } catch (\ReflectionException $e) {
                throw new \InvalidArgumentException(sprintf('Unable to load class "%s"', $class));
            }

            $map = array_merge($map, self::getClassHierarchy($reflectionClass));
        }

        return $map;
    }