protected function getExtraMethodConfig($method)
    {
        // Lazy define methods
        if (!isset(self::$extra_methods[static::class])) {
            $this->defineMethods();
        }

        if (isset(self::$extra_methods[static::class][strtolower($method)])) {
            return self::$extra_methods[static::class][strtolower($method)];
        }
        return null;
    }