Get list of used coupon names in discount rules

Retrieve a list of used coupon names in discount rules.

if(class_exists('\Wdr\App\Router')){
    $manage_discount = \Wdr\App\Router::$manage_discount;
    $calculator = $manage_discount::$calculator;
    $used_coupons = $calculator::getUsedCoupons();
    //$used_coupons -> here you get used coupon names in discount rules as an array
}