public static function locate($configOption)
    {
        $configurationFile = static::CONFIG_FILENAME;
        if (is_dir($configOption)) {
            $configurationFile = $configOption . DIRECTORY_SEPARATOR . $configurationFile;
        }
        if (file_exists($configOption) && is_file($configOption)) {
            return realpath($configOption);
        }
        if (file_exists($configurationFile)) {
            return realpath($configurationFile);
        }
        if (file_exists($configurationFile . '.dist')) {
            return realpath($configurationFile . '.dist');
        }

        return null;
    }