/**
  * @param ThemeAwareTenantInterface $defaultTenant
  *
  * @throws \Exception if there is no default tenant
  */
 private function assignDefaultTheme(ThemeAwareTenantInterface $defaultTenant)
 {
     // Only assign default theme if no theme has yet been assigned to default tenant
     if (null === $defaultTenant->getThemeName()) {
         $defaultTenant->setThemeName(self::DEFAULT_THEME_NAME);
         $documentManager = $this->getContainer()->get('swp.object_manager.tenant');
         $documentManager->flush();
     }
 }