What is "orcl" in the following pyalgotrade code? Further, i have a csv file and how can i upload data from it into my code?

I wanted to implement my own strategy for backtesting but am unable to modify the code according to my needsfrom pyalgotrade.tools import yahoofinanceyahoofinance.download_daily_bars('orcl', 2000, 'orcl-2000.csv')from pyalgotrade import strategyfrom pyalgotrade.barfeed import yahoofeedfrom pyalgotrade.technical import ma#class to create objectsclass MyStrategy(strategy.BacktestingStrategy): def __init__(self, feed, instrument): strategy.BacktestingStrategy.__init__(self, feed) # We want a 15 period SMA over the closing prices. ...Read more