public static function findOrMake(Reservation $reservation)
    {
        if (!$modifier = $reservation->PriceModifiers()->find('ClassName', self::class)) {
            $modifier = self::create();
            $modifier->write();
        }

        return $modifier;
    }
public static function findOrMake(Reservation $reservation)
    {
        if (!$modifier = $reservation->PriceModifiers()->find('ClassName', self::class)) {
            $modifier = self::create();
            $modifier->write();
        }

        return $modifier;
    }
public static function findOrMake ( Reservation $ reservation ) { if ( ! $ modifier = $ reservation -> PriceModifiers ( ) -> find ( 'ClassName' , self :: class ) ) { $ modifier = self :: create ( ) ; $ modifier -> write ( ) ; } return $ modifier ; }
Create a tax modifier if it does not already exists

@param Reservation $reservation

@return TaxModifier|\DataObject|null|static
Create a tax modifier if it does not already exists