public function getConfigTreeBuilder()
{
$treeBuilder = new TreeBuilder();
$rootNode = $treeBuilder->root('sylius_taxation');
$rootNode->addDefaultsIfNotSet()->children()->scalarNode('driver')->defaultValue(SyliusResourceBundle::DRIVER_DOCTRINE_ORM)->end()->end();
$this->addClassesSection($rootNode);
return $treeBuilder;
}