Contao\CoreBundle\DependencyInjection\Configuration::getConfigTreeBuilder PHP Method

    public function getConfigTreeBuilder()
    {
        $treeBuilder = new TreeBuilder();
        $rootNode = $treeBuilder->root('contao');
        $rootNode->children()->booleanNode('prepend_locale')->defaultFalse()->end()->scalarNode('encryption_key')->isRequired()->cannotBeEmpty()->end()->scalarNode('url_suffix')->defaultValue('.html')->end()->scalarNode('upload_path')->cannotBeEmpty()->defaultValue('files')->validate()->ifTrue(function ($v) {
            return preg_match('@^(app|assets|contao|plugins|share|system|templates|vendor|web)(/|$)@', $v);
        })->thenInvalid('%s')->end()->end()->scalarNode('csrf_token_name')->cannotBeEmpty()->defaultValue('contao_csrf_token')->end()->booleanNode('pretty_error_screens')->defaultValue(!$this->debug)->end()->integerNode('error_level')->min(-1)->max(32767)->defaultValue(E_ALL & ~E_NOTICE & ~E_DEPRECATED & ~E_USER_DEPRECATED)->end()->arrayNode('image')->addDefaultsIfNotSet()->children()->booleanNode('bypass_cache')->defaultValue($this->debug)->end()->scalarNode('target_path')->defaultValue('assets/images')->end()->arrayNode('valid_extensions')->prototype('scalar')->end()->defaultValue(['jpg', 'jpeg', 'gif', 'png', 'tif', 'tiff', 'bmp', 'svg', 'svgz'])->end()->arrayNode('imagine_options')->addDefaultsIfNotSet()->children()->integerNode('jpeg_quality')->defaultValue(80)->end()->scalarNode('interlace')->defaultValue(ImageInterface::INTERLACE_PLANE)->end()->end()->end()->end()->end()->arrayNode('security')->addDefaultsIfNotSet()->children()->booleanNode('disable_ip_check')->defaultFalse()->end()->end()->end()->variableNode('localconfig')->end()->end();
        return $treeBuilder;
    }

 /**
  * Tests the object instantiation.
  */
 public function testInstantiation()
 {
     $this->assertInstanceOf('Contao\\CoreBundle\\DependencyInjection\\Configuration', $this->configuration);
     $this->assertInstanceOf('Symfony\\Component\\Config\\Definition\\Builder\\TreeBuilder', $this->configuration->getConfigTreeBuilder());
 }