I am trying to define sma's for different symbols, and i would like to parameterize them individually because i do not wish each symbol to have sma's with the same parameters as the other symbosl. However, I am having rouble accessing my data in the OnData function. Mainly, the line "self.window.Add(data["EURUSD"])" is where i seem to be having running into issues. If i incorporate another symbol within the brackets (ex: ["EURUSD", "USDJPY"] )it throws an error saying "Object reference not set to an instance of an object". Is there an efficient way i can define multiple sma's each with its own parameters and then access them each individually in the OnData function? I also need the values to be stored in a rolling window so i can access specific indecies of each sma. Any help would really be greatly appreciated 

Thank you!!