python - 类型错误 : unsupported operand type(s) for *: 'instancemethod' and 'int'

Question

我正在尝试调试一些Python(对该语言的了解几乎为零)。在某些代码中，有一行:

self.min_spread = self.exchange.account.get_fee * 2

这会返回错误:

Traceback (most recent call last):
  File "launch.py", line 33, in <module>
    main()
  File "launch.py", line 28, in main
    bot = marketmaker.MarketMaker(exchange, pair)
  File "T:\mm-1.01\src\strategies\marketmaker.py", line 22, in __init__
    self.min_spread = self.exchange.account.get_fee * 2
TypeError: unsupported operand type(s) for *: 'instancemethod' and 'int'

经过一番研究，我在 get_fee 之后添加了括号，但这没有效果。怎么了？

这是 Python 2.7。

编辑:

为了澄清，如果我添加括号，错误将变为:

  File "T:\mm-1.01\src\strategies\marketmaker.py", line 22, in __init__
    self.min_spread = self.exchange.account.get_fee() * 2
TypeError: unsupported operand type(s) for *: 'instancemethod' and 'int'

编辑:

这是帐户类别:

class Account():


    def __init__(self, agent):
        self.agent = agent
        self._account()

    def _account(self):
        pass

    def get_balance(self):
        self._update_balance()
        return self.balance

    def get_fee(self):
        return self.get_fee

    def get_open_orders(self):
        self._update_open_orders()
        return self.open_orders

    def cancel(self, order_id):
        pass

    def cancel_all(self, order_type='all'):
        if order_type == 'all':
            for order in self.get_open_orders():
                self.cancel(order['order_id'])
        else:
            for order in self.get_open_orders():
                if order['type'] == order_type:
                    self.cancel(order['order_id'])

Answer 1

似乎您忘记在函数调用后添加 ()，所以:

self.exchange.account.get_fee() * 2

经过进一步研究，您的函数本身似乎有问题:

def get_fee(self):
    return self.get_fee

现在它返回self.get_fee，这是一个实例方法，它不返回任何值。这就是您收到错误的原因。