private function addBlocksSection(ArrayNodeDefinition $node)
    {
        $node
            ->children()
                ->arrayNode('blocks')
                    ->addDefaultsIfNotSet()
                    ->children()
                        ->arrayNode('subscribe')
                            ->addDefaultsIfNotSet()
                            ->children()
                                ->scalarNode('view')->defaultValue('OpiferMailingListBundle:Block:subscribe.html.twig')->end()
                                ->arrayNode('templates')
                                    ->prototype('scalar')->end()
                                    ->normalizeKeys(false)
                                    ->useAttributeAsKey('name')
                                    ->defaultValue([])
                                ->end()
                            ->end()
                        ->end()
                    ->end()
                ->end()
            ->end()
        ;
    }