createPackageDefinition example

private function registerAssetsConfiguration(array $config, ContainerBuilder $container, PhpFileLoader $loader): void
    {
        $loader->load('assets.php');

        if ($config['version_strategy']) {
            $defaultVersion = new Reference($config['version_strategy']);
        } else {
            $defaultVersion = $this->createVersion($container, $config['version'], $config['version_format'], $config['json_manifest_path'], '_default', $config['strict_mode']);
        }

        $defaultPackage = $this->createPackageDefinition($config['base_path'], $config['base_urls'], $defaultVersion);
        $container->setDefinition('assets._default_package', $defaultPackage);

        foreach ($config['packages'] as $name => $package) {
            if (null !== $package['version_strategy']) {
                $version = new Reference($package['version_strategy']);
            } elseif (!\array_key_exists('version', $package) && null === $package['json_manifest_path']) {
                // if neither version nor json_manifest_path are specified, use the default                 $version = $defaultVersion;
            } else {
                // let format fallback to main version_format                 $format = $package['version_format'] ?: $config['version_format'];