code: def ReqConnect(self, front: str):
          
          self.t.CreateApi()
          spi = self.t.CreateSpi()
          self.t.RegisterSpi(spi)
  
          self.t.OnFrontConnected = self._OnFrontConnected
          self.t.OnRspUserLogin = self._OnRspUserLogin
          self.t.OnFrontDisconnected = self._OnFrontDisconnected
          # self.t.OnRspUserLogout = self._OnRspUserLogout
          self.t.OnRspSettlementInfoConfirm = self._OnRspSettlementInfoConfirm
          self.t.OnRtnOrder = self._OnRtnOrder
          self.t.OnRtnTrade = self._OnRtnTrade
          self.t.OnRspOrderInsert = self._OnRspOrder
          self.t.OnErrRtnOrderInsert = self._OnErrOrder
          self.t.OnRspOrderAction = self._OnRspOrderAction
          self.t.OnRtnInstrumentStatus = self._OnRtnInstrumentStatus
          self.t.OnRspQryInstrument = self._OnRspQryInstrument
          self.t.OnRspQryTradingAccount = self._OnRspQryAccount
          self.t.OnRspQryInvestorPosition = self._OnRspQryPosition
          self.t.OnRspQryInvestorPositionDetail = self._OnRspQryPositionDetail
          self.t.OnRtnTradingNotice = self._OnRtnNotice
          self.t.OnRtnQuote = self._OnRtnQuote
          self.t.OnErrRtnQuoteInsert = self._OnErrRtnQuote
          self.t.OnErrRtnForQuoteInsert = self._OnErrForQuoteInsert
  
          self.front_address = front
          self.t.RegCB()
          self.t.RegisterFront(front)
          self.t.SubscribePrivateTopic(0)  # restart 同步处理order trade
          self.t.SubscribePublicTopic(0)
          self.t.Init()
docs: 连接交易前置
  
          :param front: