commission.py 文件源码

def __init__(self,
                 cost,
                 exchange_fee,
                 min_trade_cost=DEFAULT_MINIMUM_COST_PER_FUTURE_TRADE):
        # If 'cost' or 'exchange fee' are constants, use a dummy mapping to
        # treat them as a dictionary that always returns the same value.
        # NOTE: These dictionary does not handle unknown root symbols, so it
        # may be worth revisiting this behavior.
        if isinstance(cost, (int, float)):
            self._cost_per_contract = DummyMapping(float(cost))
        else:
            # Cost per contract is a dictionary. If the user's dictionary does
            # not provide a commission cost for a certain contract, fall back
            # on the pre-defined cost values per root symbol.
            self._cost_per_contract = defaultdict(
                lambda: DEFAULT_PER_CONTRACT_COST, **cost
            )

        if isinstance(exchange_fee, (int, float)):
            self._exchange_fee = DummyMapping(float(exchange_fee))
        else:
            # Exchange fee is a dictionary. If the user's dictionary does not
            # provide an exchange fee for a certain contract, fall back on the
            # pre-defined exchange fees per root symbol.
            self._exchange_fee = merge(
                FUTURE_EXCHANGE_FEES_BY_SYMBOL, exchange_fee,
            )

        self.min_trade_cost = min_trade_cost or 0