AttributeError：'NoneType'对象没有属性'conId'

如何解决AttributeError：'NoneType'对象没有属性'conId'

我正在使用Interactive brokers python API来对AMD进行限价订单。到目前为止，该代码是：

from ibapi.client import EClient
from ibapi.wrapper import EWrapper
from ibapi.contract import Contract
from ibapi.order import Order
import threading
import time


class TradingApp(EWrapper,EClient):
    def __init__(self):
        EClient.__init__(self,self)
 
    
    def nextValidId(self,orderId):
        self.nextValidId = orderId

def websocket_con():
    app.run()
    
        
app = TradingApp()
app.connect("127.0.0.1",7497,clientId=13)

con_thread = threading.Thread(target=websocket_con,daemon=True)
con_thread.start()
time.sleep(1)

def Usstock(symbol,secType='STK',Currency='USD',exchnange = 'SMART'):
    contract=Contract()
    contract.symbol = symbol
    contract.secType = secType
    contract.currency = Currency
    contract.exchange = exchnange

def limit_order(direction,quantity,price):
    order=Order()
    order.action = direction
    order.orderType = 'LMT'
    order.totalQuantity = quantity
    order.lmtPrice = price
order_id = app.nextValidId
app.placeOrder(order_id,Usstock('AMD'),limit_order('BUY',10,50))

虽然我正在运行它，但是却收到错误消息：

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-49-407bad8e9645> in <module>
     40     order.lmtPrice = price
     41 order_id = app.nextValidId
---> 42 app.placeOrder(order_id,50))

~\AppData\Roaming\Python\python37\site-packages\ibapi-9.76.1-py3.7.egg\ibapi\client.py in placeOrder(self,orderId,contract,order)
   1041         # send contract fields
   1042         if self.serverVersion() >= MIN_SERVER_VER_PLACE_ORDER_CONID:
-> 1043             flds.append(make_field( contract.conId))
   1044         flds += [make_field( contract.symbol),1045             make_field( contract.secType),AttributeError: 'nonetype' object has no attribute 'conId'

但是我不知道我在哪里使用了'conId'或为什么显示此错误。有任何想法吗？谢谢！

解决方法

问题在于，在这两个函数的末尾，我应该添加返回合同和订单的内容，因为如果我做的不是全部，则只是对函数中的组件进行修饰。因此代码应为：

def Contract_Order():
    contract=Contract()
    contract.symbol = 'AMD'
    contract.secType = 'STK'
    contract.currency = 'USD'
    contract.exchange = 'ISLAND'
    return contract

def Limit_Order():
    order=Order()
    order.action = 'BUY'
    order.orderType = 'LMT'
    order.totalQuantity = 10
    order.lmtPrice = 100
    return order

只需添加退货合同和退货订单即可解决