code: def send_order(self, acc_id, amount, symbol, _type, price=0, site='Pro', _async=False):
          
          assert site in ['Pro', 'HADAX']
          assert _type in u.ORDER_TYPE
          params = {
              'account-id': acc_id,
              'amount': amount,
              'symbol': symbol,
              'type': _type,
              'source': 'api'
          }
          if price:
              params['price'] = price
  
          path = f'/v1{"/" if site == "Pro" else "/hadax/"}order/orders/place'
          return api_key_post(params, path, _async=_async)
docs: 创建并执行订单
          :param amount:
          :param source: 如果使用借贷资产交易，请在下单接口,请求参数source中填写'margin-api'
          :param symbol:
          :param _type: 可选值 {buy-market：市价买, sell-market：市价卖, buy-limit：限价买, sell-limit：限价卖, buy-ioc：IOC买单, sell-ioc：IOC卖单}
          :param price:
          :return: