src/DependencyInjection/Configuration.php
private function addDefaultEventSection($rootNode)
    {
        $rootNode
            ->children()
                ->booleanNode('base_collectors')
                    ->defaultFalse()
                ->end()
                ->booleanNode('console_events')
                    ->defaultFalse()
                ->end();
    }
private function addDefaultEventSection($rootNode)
    {
        $rootNode
            ->children()
                ->booleanNode('base_collectors')
                    ->defaultFalse()
                ->end()
                ->booleanNode('console_events')
                    ->defaultFalse()
                ->end();
    }
addDefaultEventSection

@param mixed $rootNode