need SIMPLE HELP !

[tazosmr]

hello.

in product.php i need to detect, if the product already is discounted by VOUCHER.

 

i have tried these function, but had not succeed:

 

1) Order::getCartRules();

2) isDiscounted();

3) discountExists($discountName, $id_discount = 0);

4) parent::cartRuleExists($discountName);

5) isset($order_invoice);

 

 

which one detects if there is voucher applied?