private function mapInstallmentPrices($installmentPrices)
 {
     $prices = array();
     foreach ($installmentPrices as $index => $installmentPrice) {
         $price = new InstallmentPrice();
         if (isset($installmentPrice->installmentPrice)) {
             $price->setInstallmentPrice($installmentPrice->installmentPrice);
         }
         if (isset($installmentPrice->totalPrice)) {
             $price->setTotalPrice($installmentPrice->totalPrice);
         }
         if (isset($installmentPrice->installmentNumber)) {
             $price->setInstallmentNumber($installmentPrice->installmentNumber);
         }
         $prices[$index] = $price;
     }
     return $prices;
 }