private function addResolveTargetDocumentsSection(ArrayNodeDefinition $rootNode)
    {
        $rootNode
            ->fixXmlConfig('resolve_target_document')
            ->children()
                ->arrayNode('resolve_target_documents')
                    ->useAttributeAsKey('interface')
                    ->prototype('scalar')
                        ->cannotBeEmpty()
                    ->end()
                ->end()
            ->end();
    }