I forgot the line code:

/**
    * Returns the country code for the country that applies to the order.
    * It only takes into account what has actually been saved.
    * @return String (country code)
    **/
   public function Country() {return $this->getCountry();}
   public function getCountry() {
      $countryCodes = array(
         "Billing" => "",
         "Shipping" => ""
      );
      if($this->BillingAddressID) {
         $billingAddress = BillingAddress::get()->byID($this->BillingAddressID)
         
Line 1978    if($billingAddress) {
            if($billingAddress->Country) {
               $countryCodes["Billing"] = $billingAddress->Country;
            }
         }
      }
      if($this->ShippingAddressID && $this->UseShippingAddress) {
         $shippingAddress = BillingAddress::get()->byID($this->ShippingAddressID)
         if($shippingAddress) {
            if($shippingAddress->ShippingCountry) {
               $countryCodes["Shipping"] = $shippingAddress->ShippingCountry;
            }
         }
      }
      if(count($countryCodes)) {
         if(EcommerceConfig::get("OrderAddress", "use_shipping_address_for_main_region_and_country") && $countryCodes["Shipping"]) {
            return $countryCodes["Shipping"];
         }
         return $countryCodes["Billing"];
      }
   }