public static function getPeriodToFrequency()
    {
        return array(
            Schedule::PERIOD_NEVER => Piwik::translate('General_Never'),
            Schedule::PERIOD_DAY   => Piwik::translate('General_Daily'),
            Schedule::PERIOD_WEEK  => Piwik::translate('General_Weekly'),
            Schedule::PERIOD_MONTH => Piwik::translate('General_Monthly'),
        );
    }