    function acceptCounterOffer(
        Order memory order,
        bytes calldata signature,
        Order memory originalOrder
    ) public payable returns (uint256 positionId) {
        // cancel the original order
        cancel(originalOrder);


        // accept the counter offer
        uint256[] memory floorAssetTokenIds = new uint256[](0);
        positionId = fillOrder(order, signature, floorAssetTokenIds);
    }
    function cancel(Order memory order) public {
        require(msg.sender == order.maker, "Not your order");


        bytes32 orderHash = hashOrder(order);


        // mark the order as cancelled
        cancelledOrders[orderHash] = true;


        emit CancelledOrder(orderHash, order);
    }
