src/DependencyInjection/Configuration.php
private function getParentNode()
    {
        $node = $this->createTreeBuilderNode('_parent');

        $node
            ->children()
                ->scalarNode('type')->end()
                ->scalarNode('property')->defaultValue(null)->end()
                ->scalarNode('identifier')->defaultValue('id')->end()
            ->end()
        ;

        return $node;
    }
private function getParentNode()
    {
        $node = $this->createTreeBuilderNode('_parent');

        $node
            ->children()
                ->scalarNode('type')->end()
                ->scalarNode('property')->defaultValue(null)->end()
                ->scalarNode('identifier')->defaultValue('id')->end()
            ->end()
        ;

        return $node;
    }
Returns the array node used for "_parent".