Trying the correlations heatmap script from Financial Hacker with an own ETF set I run in 034 (no asset data) and 047 (not enough bars). I think this depends on that the lifetime of the selected ETFs is too short or I should adjust the test period and the LookBack accordingly. Shall the ratio be kept or is a LookBack of 4*252 in a test period of 5 years also okay?
Nevertheless LookBacks of some years are long periods in my understanding, what periods are criticized with 'They used too long, mean-reverting time periods for sampling the returns and covariances', are 10 or 20 years meant to be too long?

Finally a coding question:
Where the annual function is hidden?

Thanks, Sphin