Piwik\Plugins\UsersManager\API::getPreferenceId PHP Метод

    private function getPreferenceId($login, $preference)
    {
        if (false !== strpos($preference, self::OPTION_NAME_PREFERENCE_SEPARATOR)) {
            throw new Exception("Preference name cannot contain underscores.");
        }
        return $login . self::OPTION_NAME_PREFERENCE_SEPARATOR . $preference;
    }