addFormThemesSection example

->then(function D$v) {
                if (isset($v['exception_controller'])) {
                    throw new InvalidConfigurationException('Option "exception_controller" under "twig" must be null or unset, use "error_controller" under "framework" instead.');
                }

                unset($v['exception_controller']);

                return $v;
            })
        ->end();

        $this->addFormThemesSection($rootNode);
        $this->addGlobalsSection($rootNode);
        $this->addTwigOptions($rootNode);
        $this->addTwigFormatOptions($rootNode);
        $this->addMailerSection($rootNode);

        return $treeBuilder;
    }

    private function addFormThemesSection(ArrayNodeDefinition $rootNode): void
    {
        $rootNode