public function getExpirationDate($currentDate)
    {
        $numberOfDays = Mage::helper('sheep_debug')->getPersistLifetime();

        return date(self::DATE_FORMAT, strtotime("-{$numberOfDays} days {$currentDate}"));
    }
public function getExpirationDate($currentDate)
    {
        $numberOfDays = Mage::helper('sheep_debug')->getPersistLifetime();

        return date(self::DATE_FORMAT, strtotime("-{$numberOfDays} days {$currentDate}"));
    }
public function getExpirationDate ( $ currentDate ) { $ numberOfDays = Mage :: helper ( 'sheep_debug' ) -> getPersistLifetime ( ) ; return date ( self :: DATE_FORMAT , strtotime ( "-{$numberOfDays} days {$currentDate}" ) ) ; }
Removes configured number of days from specified date

@param string $currentDate
@return bool|string
Removes configured number of days from specified date