[int] 卖方向挂单量

def sell_close_order_quantity(self):
        """
        [int] 卖方向挂单量
        """
        return sum(order.unfilled_quantity for order in self.open_orders if order.side == SIDE.SELL and
                   order.position_effect in [POSITION_EFFECT.CLOSE, POSITION_EFFECT.CLOSE_TODAY])