I am getting an error and cannot seem to get this code to add the necessary data to my rolling window, or I am making some other mistake I am not able to recognize. Can someone with experience using a rolling window of indicator values for futures trading take a look at this, as always it is much appreciated. 

class BBConsolidatorTest(QCAlgorithm):

    def Initialize(self):
        self.SetStartDate(2020, 5, 1) 
        self.SetEndDate(2020, 6, 4)
        self.SetCash(100000) 

        future = self.AddFuture(Futures.Indices.SP500EMini, Resolution.Minute)
        future.SetFilter(lambda x: x.FrontMonth().OnlyApplyFilterAtMarketOpen())

        self.symbol = None

        self.BBIndicator = BollingerBands(20, 2, MovingAverageType.Simple)
        self.BBUpperWindow = RollingWindow[float](4)
        self.BBLowerWindow = RollingWindow[float](4)
        
        self.RSIIndicator = RelativeStrengthIndex(10, MovingAverageType.Exponential)
        self.RSIWindow = RollingWindow[float](4)
        
        self.curr_contract = None
        self.SetWarmUp(timedelta(days=30))
        
  

    def OnData(self, slice):
        for i, chain in enumerate(slice.FutureChains):
            contracts = [contract for contract in chain.Value]
            if len(contracts) > 0:
                contract = contracts[0]
                if self.curr_contract is not None and self.curr_contract != contract:
                    self.curr_contract = contracts[0]
                    self.BBIndicator.Reset()
                    self.BBUpperWindow.Reset()
                    self.BBLowerWindow.Reset()
                    self.RSIIndicator.Reset()
                    self.BBIndicator.Update(slice.Time, contract.LastPrice)
                    
                if self.BBIndicator.IsReady:
                    self.BBUpperWindow.Add(self.BBIndicator.UpperBand.Current.Value)
                    self.BBLowerWindow.Add(self.BBIndicator.LowerBand.Current.Value)
                if self.RSIIndicator.IsReady:
                    self.RSIWindow.Add(self.RSIIndicator.Current.Value)
                    
                if self.symbol is not None:
                    price = self.Securities[self.symbol].Price
                if not self.Portfolio.Invested:
                    if price < self.BBLowerWindow[0]:
                        if self.RSIWindow[0] > self.RSIWindow[1]:
                            self.MarketOrder(self.curr_contract, 1)
                    
        
                    
        

    def OnSecuritiesChanged(self, changes):
        if len(changes.RemovedSecurities) > 0:
            if self.symbol is not None and self.consolidator is not None:
                self.BBIndicator.Reset()
                self.RSIIndicator.Reset()

        self.symbol = changes.AddedSecurities[0].Symbol

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