function getActiveSellOrders(uint offset, uint16 chunkSize)
    external view returns (uint[4][]) {
        uint limit = SafeMath.min(offset.add(chunkSize), activeSellOrders.length);
        uint[4][] memory response = new uint[4][](limit.sub(offset));
        for (uint i = offset; i < limit; i++) {
            uint64 orderId = activeSellOrders[i];
            Order storage order = sellTokenOrders[orderId];
            response[i - offset] = [orderId, uint(order.maker), order.price, order.amount];
        }
        return response;
    }