DependencyInjection/Source/JWKSetSource/Keys.php
public function addConfiguration(NodeDefinition $node)
    {
        parent::addConfiguration($node);
        $node
            ->children()
                ->arrayNode('id')
                    ->prototype('scalar')
                    ->end()
                    ->isRequired()
                ->end()
            ->end();
    }
public function addConfiguration(NodeDefinition $node)
    {
        parent::addConfiguration($node);
        $node
            ->children()
                ->arrayNode('id')
                    ->prototype('scalar')
                    ->end()
                    ->isRequired()
                ->end()
            ->end();
    }
{@inheritdoc}