public function __invoke(ContainerInterface $container, $requestedName, array $options = null)
{
$config = $container->get('config');
$files = array();
if (isset($config['asset_manager']['resolver_configs']['concat'])) {
$files = $config['asset_manager']['resolver_configs']['concat'];
}
$concatResolver = new ConcatResolver($files);
return $concatResolver;
}