private function cleanSettings(User $user)
    {
        foreach ($user->getNotificationSettings() as $userNotificationSetting) {
            $this->objectManager->remove($userNotificationSetting);
        }

        $user->getNotificationSettings()->clear();

        foreach ($user->getSettings() as $userSetting) {
            $this->objectManager->remove($userSetting);
        }

        $user->getSettings()->clear();
    }