public function initialize(OutputInterface $output = null, $purge = false)
    {
        $output = $output ?: new NullOutput();

        arsort($this->initializerMap);

        foreach (array_keys($this->initializerMap) as $initializerId) {
            $output->writeln(sprintf('<comment>%s</>', $initializerId));
            $initializer = $this->container->get($initializerId);
            $initializer->initialize($output, $purge);
        }
        $output->write(PHP_EOL);
        $output->writeln('<comment>*</> Legend: [+] Added [*] Updated [-] Purged [ ] No change');
    }