protected function _fillOutDiscount(IDiscount $discountPayload, array $discountData)
    {
        return $discountPayload
            ->setAmount($this->_nullCoalesce($discountData, 'amount', 0.00))
            ->setAppliedCount($this->_nullCoalesce($discountData, 'applied_count', null))
            ->setCode($this->_nullCoalesce($discountData, 'code', null))
            ->setDescription($this->_nullCoalesce($discountData, 'description', null))
            ->setEffectType($this->_nullCoalesce($discountData, 'effect_type', null))
            ->setId($this->_nullCoalesce($discountData, 'id', null));
    }