public static function normalizeConnection(array $connection)
    {
        $normal = [ ];

        if (array_key_exists('options', $connection)) {
            $normal['options'] = $connection['options'];
            unset($connection['options']);
        }

        foreach ($connection as $host) {
            $normal = array_merge($normal, static::normalizeHost($host));
        }

        return $normal;
    }