/** * @param Price $priceToSubtract * @return Price */ public function subtract(Price $priceToSubtract) { $this->checkCurrencies($this->getCurrency(), $priceToSubtract->getCurrency()); if ($this->isGreaterThan($priceToSubtract)) { $newGross = $this->getGross() - $priceToSubtract->getGross(); $newNett = $this->getNett() - $priceToSubtract->getNett(); return new Price($newNett, $newGross, $this->getCurrencySymbol(), $this->getTaxForPrices($this, $priceToSubtract)); } return Price::buildEmpty($this->getCurrencySymbol()); }