public static function configTransport($key, $config = null)
    {
        deprecationWarning('Email::configTransport() is deprecated. Use TransportFactory::setConfig() or TransportFactory::getConfig() instead.');

        if ($config === null && is_string($key)) {
            return TransportFactory::getConfig($key);
        }
        if ($config === null && is_array($key)) {
            TransportFactory::setConfig($key);

            return null;
        }

        TransportFactory::setConfig($key, $config);
    }