src/DependencyInjection/Configuration.php
public function getConfigTreeBuilder()
    {
        $treeBuilder = new TreeBuilder();

        $treeBuilder
            ->root('endroid_twitter')
                ->children()
                    ->scalarNode('consumer_key')->isRequired()->cannotBeEmpty()->end()
                    ->scalarNode('consumer_secret')->isRequired()->cannotBeEmpty()->end()
                    ->scalarNode('access_token')->defaultValue(null)->end()
                    ->scalarNode('access_token_secret')->defaultValue(null)->end()
                    ->scalarNode('api_url')->defaultValue(null)->end()
                    ->scalarNode('proxy')->defaultValue(null)->end()
                    ->integerNode('timeout')->defaultValue(5)->end()
                    ->booleanNode('verify_peer')->defaultValue(true)->end()
                ->end()
        ;

        return $treeBuilder;
    }
public function getConfigTreeBuilder()
    {
        $treeBuilder = new TreeBuilder();

        $treeBuilder
            ->root('endroid_twitter')
                ->children()
                    ->scalarNode('consumer_key')->isRequired()->cannotBeEmpty()->end()
                    ->scalarNode('consumer_secret')->isRequired()->cannotBeEmpty()->end()
                    ->scalarNode('access_token')->defaultValue(null)->end()
                    ->scalarNode('access_token_secret')->defaultValue(null)->end()
                    ->scalarNode('api_url')->defaultValue(null)->end()
                    ->scalarNode('proxy')->defaultValue(null)->end()
                    ->integerNode('timeout')->defaultValue(5)->end()
                    ->booleanNode('verify_peer')->defaultValue(true)->end()
                ->end()
        ;

        return $treeBuilder;
    }
{@inheritdoc}