result_t<std::vector<result_t<order_t>>> connector::new_batch_orders(const std::vector<order_t>& orders) {
    std::vector<api::new_order_request_t> request(orders.size());
    result_t<std::vector<result_t<order_t>>> result;
    for (size_t i = 0; i < orders.size(); ++i) {
        const order_t& order = orders[i];
        request[i].symbol = order.symbol->symbol;
        request[i].side = e_side_to_str(order.side);
        request[i].type = e_type_to_str(order.type);
        if (order.type == e_type::MARKET) {
            if (order.side == e_side::BUY) {
                if (order.amount.initialized()) {
                    request[i].quote_order_qty = order.amount.to_string();
                } else if (order.quantity.initialized()) {
                    book_t cur = local_get_book(order.symbol).value;
                    double price = 0;
                    if (cur.ask_price.initialized()) {
                        price = cur.ask_price.to_double();
                    } else {
                        result.code = e_market_error::NO_EXIST_OPPONENT_ORDER;
                        return result;
                    }
                    request[i].quote_order_qty = order.symbol->make_amount(price * order.quantity.to_double()).to_string();
                } else {
                    result.code = e_market_error::AMOUNT_NULL_INVALID;
                    return result;
                }
            } else {
                if (order.quantity.initialized()) {
                    request[i].quantity = order.quantity.to_string();
                } else if (order.amount.initialized()) {
                    book_t cur = local_get_book(order.symbol).value;
                    double price = 0;
                    if (cur.bid_price.initialized()) {
                        price = cur.bid_price.to_double();
                    } else {
                        result.code = e_market_error::NO_EXIST_OPPONENT_ORDER;
                        return result;
                    }
                    request[i].quantity = order.symbol->make_quantity(order.amount.to_double() / price).to_string();
                } else {
                    result.code = e_market_error::AMOUNT_NULL_INVALID;
                    return result;
                }
            }
        } else {
            request[i].price = order.price.to_string();
            if (order.quantity.initialized()) {
                request[i].quantity = order.quantity.to_string();
            } else if (order.amount.initialized()) {
                request[i].quantity = order.symbol->make_quantity(order.amount.to_double() / order.price.to_double()).to_string();
            } else {
                result.code = e_market_error::AMOUNT_NULL_INVALID;
                return result;
            }
        }
    }
    result_t<std::vector<result_t<api::new_order_response_t>>> response = api_.new_batch_orders(std::move(request));
    if (response.code != e_market_error::OK) {
        result.code = response.code;
        return result;
    }
    result.value = std::vector<result_t<order_t>>(response.value.size()); // my code!
    for (size_t i = 0; i < response.value.size(); ++i) {
        const order_t& order = orders[i];
        if (response.value[i].code != e_market_error::OK) {
            result.value[i].code = response.value[i].code;
        } else {
            result.value[i].value.symbol = order.symbol;
            result.value[i].value.side = response.value[i].value.side;
            result.value[i].value.type = response.value[i].value.type;
            result.value[i].value.price = order.price;
            result.value[i].value.quantity = order.quantity;
            result.value[i].value.amount = order.amount;
            result.value[i].value.update_time = response.value[i].value.transact_time;
        }
    }
    return result;
}