Mutable default arguments

[jrycw]

class Strategy(object):

    def backtest(self, ohlcv, variables=dict(),
                         filters=dict(), lookback=None, plot=False,
                         signals=False, side='long', cscv_nbins=10,
                         cscv_objective=lambda r: r.mean(), html=None, compounded=True, execution_price='close', **args):

There might be a potential issue if using dictionary as the default argument for variables and filters, since dictionary is mutable.

I will argue that using None as the default argument might be a safer approach.

[koreal6803]

Thanks for the feedback, I updated ecea8d9 to fixed it.