Trading with SMA indicator

# code to combine indicators and backtest the performance
# region imports
from AlgorithmImports import *
# endregion

class Indicators(QCAlgorithm):

    def Initialize(self):
        self.SetStartDate(2020, 1, 1)  # Set Start Date
        self.SetEndDate(2023, 1, 1)  # Set Start Date        
        self.SetCash(100000)  # Set Strategy Cash

        self.spy = self.AddEquity("AAPL", Resolution.Daily).Symbol      #set data for SPY
        self.sma = self.SMA(self.spy, 30, Resolution.Daily)            #set data for SMA
        closing_price = self.History(self.spy, 30, Resolution.Daily)["close"]   #take historic prices for SMA
        for time, price in closing_price.loc[self.spy].items():
            self.sma.Update(time,price)                                 #update first 30 values of SMA to historic prices
        


    def OnData(self, data: Slice):
        if not self.sma.IsReady:        # to check if SMA is ready or not as it is a average indicator
            return    
        
        #Another indicator to check for high and low of 60 Daily
        hist = self.History(self.spy, timedelta(252), Resolution.Daily)
        low = min(hist["low"])
        high = min(hist["high"])

        #combining both trading logics - SMA + High/Low

        price = self.Securities[self.spy].Price

        if price >= 1.05*high and self.sma.Current.Value > price:
            if not self.Portfolio[self.spy].IsLong:
                self.SetHoldings(self.spy,1)
        
        if price <= 0.95*low and self.sma.Current.Value < price:
            if not self.Portfolio[self.spy].IsShort:
                self.SetHoldings(self.spy,-1)

        self.Plot("Benchmark", "60m-High", high)
        self.Plot("Benchmark", "60m-Low", low)
        self.Plot("Benchmark", "60m-High", self.sma.Current.Value)