addMailerSection example

$this->addPropertyInfoSection($rootNode, $enableIfStandalone);
        $this->addCacheSection($rootNode, $willBeAvailable);
        $this->addPhpErrorsSection($rootNode);
        $this->addExceptionsSection($rootNode);
        $this->addWebLinkSection($rootNode, $enableIfStandalone);
        $this->addLockSection($rootNode, $enableIfStandalone);
        $this->addSemaphoreSection($rootNode, $enableIfStandalone);
        $this->addMessengerSection($rootNode, $enableIfStandalone);
        $this->addSchedulerSection($rootNode, $enableIfStandalone);
        $this->addRobotsIndexSection($rootNode);
        $this->addHttpClientSection($rootNode, $enableIfStandalone);
        $this->addMailerSection($rootNode, $enableIfStandalone);
        $this->addSecretsSection($rootNode);
        $this->addNotifierSection($rootNode, $enableIfStandalone);
        $this->addRateLimiterSection($rootNode, $enableIfStandalone);
        $this->addUidSection($rootNode, $enableIfStandalone);
        $this->addHtmlSanitizerSection($rootNode, $enableIfStandalone);
        $this->addWebhookSection($rootNode, $enableIfStandalone);
        $this->addRemoteEventSection($rootNode, $enableIfStandalone);

        return $treeBuilder;
    }

    

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
            ->fixXmlConfig('form_theme')
            ->children()
                ->arrayNode('form_themes')
                    ->addDefaultChildrenIfNoneSet()