DependencyInjection/Configuration.php
public function getConfigTreeBuilder()
    {
        $treeBuilder = new TreeBuilder();
        $rootNode = $treeBuilder->root($this->alias);

        foreach ($this->service_sources as $service_source) {
            $service_source->getNodeDefinition($rootNode);
        }

        return $treeBuilder;
    }
public function getConfigTreeBuilder()
    {
        $treeBuilder = new TreeBuilder();
        $rootNode = $treeBuilder->root($this->alias);

        foreach ($this->service_sources as $service_source) {
            $service_source->getNodeDefinition($rootNode);
        }

        return $treeBuilder;
    }
{@inheritdoc}