Hi, please help, i tried my first algo as i learned in a tutorial but i cannot backtest it. Where is the mistake? I guess it is about the downloading of the historical data or something like that?

 

import numpy as np

class BasicTemplateAlgorithm(QCAlgorithm):
   

    def Initialize(self):
     
        self.SetStartDate(2014,10,07)  #Set Start Date
        self.SetEndDate(2014,10,11)    #Set End Date
        self.SetCash(100000)           #Set Strategy Cash

        self.AddEquity("AAL", Resolution.Daily)
        self.AddEquity("UAL", Resolution.Daily)
        
        self.long_on_spread = False
        self.shorting_spread = False

    def OnData(self, data):
        
        prices = self.History(["AAL","UAL"], 3)
        
        short_prices = prices.iloc[-1:]
        
        mavg_30 = np.mean(prices["AAL"]-prices["UAL"])
        std_30 = np.std(prices["AAL"]-prices["UAL"])
        
        mavg_1 = np.mean(short_prices["AAL"] - short_prices["UAL"])
        
        if std_30 > 0:
            zscore = (mavg_1 - mavg_30)/std_30
            
            if zscore > 1.0 and not self.shorting_spread:
                self.SetHoldings("AAL", -0.5)
                self.SetHoldings("UAL", 0.5)
                self.shorting_spread = True
                self.long_on_spread = False
                
            elif zscore < 1.0 and not self.long_on_spread:
                self.SetHoldings("AAL", 0.5)
                self.SetHoldings("UAL", -0.5)
                self.shorting_spread = False
                self.long_on_spread = True
                    
            elif abs(zscore) < 0.1:
                self.SetHoldings("AAL", 0)
                self.SetHoldings("UAL", 0)
                self.shorting_spread = False
                self.long_on_spread = False