ProductVariation::sellingPrice PHP Method

    public function sellingPrice()
    {
        $price = $this->Price;
        $this->extend("updateSellingPrice", $price);
        //prevent negative values
        $price = $price < 0 ? 0 : $price;
        // NOTE: Ideally, this would be dependent on the locale but as of
        // now the Silverstripe Currency field type has 2 hardcoded all over
        // the place. In the mean time there is an issue where the displayed
        // unit price can not exactly equal the multiplied price on an order
        // (i.e. if the calculated price is 3.145 it will display as 3.15.
        // so if I put 10 of them in my cart I will expect the price to be
        // 31.50 not 31.45).
        return round($price, Order::config()->rounding_precision);
    }