Hi everyone!

I have a question about using external data (specifically a csv from dropbox). I have data about events that happen that impact different stocks. The format for my CSV file is:

 "date", "symbol", "value"

While using the GetSource/Reader method it's apparent I can't have multiple symbols in my csv. Is there a way to use GetSource with a csv that has multiple symbols? Should I abandon this approach and use the `self.download` method? Where should I call this method if I want the file to be downloaded once for backtesting and everyday for live trading?