public function setShippingDiscount($shippingDiscount)
    {
        NumericValidator::validate($shippingDiscount, "Shipping Discount");
        $shippingDiscount = Formatter::formatToPrice($shippingDiscount);
        $this->shippingDiscount = $shippingDiscount;
        return $this;
    }
public function setShippingDiscount($shippingDiscount)
    {
        NumericValidator::validate($shippingDiscount, "Shipping Discount");
        $shippingDiscount = Formatter::formatToPrice($shippingDiscount);
        $this->shippingDiscount = $shippingDiscount;
        return $this;
    }
public function setShippingDiscount ( $ shippingDiscount ) { NumericValidator :: validate ( $ shippingDiscount , "Shipping Discount" ) ; $ shippingDiscount = Formatter :: formatToPrice ( $ shippingDiscount ) ; $ this -> shippingDiscount = $ shippingDiscount ; return $ this ; }
Amount being discounted for the shipping fee.

@param string|double $shippingDiscount

@return $this
Amount being discounted for the shipping fee .