protected function checkOptions(Container $app)
    {
        $requiredOptions = ['object_manager', 'user_class', 'firewall_name'];

        foreach ($requiredOptions as $option) {
            if (empty($app['silex_user.options'][$option])) {
                throw new LogicException(sprintf('The "%s" option must be set', $option));
            }
        }

        if (true === $this->getOption($app, 'registration.confirmation.enabled') && empty($this->getOption($app, 'registration.confirmation.from_email'))) {
            throw new LogicException('The "registration.confirmation.from_email" option must be set');
        }
    }