public function getCombinationsForUser($userGroups, $userType)
    {
        $userType = strtolower($userType);
        if ('fe' !== $userType && 'be' !== $userType) {
            throw new \InvalidArgumentException('Unknown user type: ' . $userType);
        }

        return $this->getCombinationsFromDatabase($userGroups, $userType);
    }