def send_order(self,  code, price, amount, towards, order_model, market=None):
        """下单

        Arguments:
            code {[type]} -- [description]
            price {[type]} -- [description]
            amount {[type]} -- [description]
            towards {[type]} -- [description]
            order_model {[type]} -- [description]
            market:市场，SZ 深交所，SH 上交所

        Returns:
            [type] -- [description]
        """

        towards = 0 if towards == ORDER_DIRECTION.BUY else 1
        if order_model == ORDER_MODEL.MARKET:
            order_model = 4
        elif order_model == ORDER_MODEL.LIMIT:
            order_model = 0

        if market is None:
            market = QAFetch.base.get_stock_market(code)
        if not isinstance(market, str):
            raise Exception('%s不正确，请检查code和market参数' % market)
        market = market.lower()
        if market not in ['sh', 'sz']:
            raise Exception('%s不支持，请检查code和market参数' % market)

        return self.data_to_df(self.call("send_order", {
            'client_id': self.client_id,
            'category': towards,
            'price_type': order_model,
            'gddm': self.gddm_sh if market == 'sh' else self.gddm_sz,
            'zqdm': code,
            'price': price,
            'quantity': amount
        }))