Chapter 8 (02_backtesting_with_zipline)

Strategy Backtesting
#1

When I run this:

results = run_algorithm(start=start_date,
                       end=end_date,
                       initialize=initialize,
                       before_trading_start=before_trading_start,
                       capital_base=1e6,
                       data_frequency='daily',
                       bundle='quandl',
                       custom_loader=signal_loader) # need to modify zipline

print('Duration: {:.2f}s'.format(time() - start))

I get:

Warning: 0 is not a string!
Warning: 0 is not a string!
Warning: 0 is not a string!
Warning: 0 is not a string!

I’m I missing something? The backtest in the zipline demo ran just fine but this one has not worked.