Older versions of scipy.stats.nanstd might not handle axis < 0.
Older versions of scipy.stats.nanstd might not handle axis < 0.

Just a wild guess based on a user reporting a
test failure.

pydata/bottleneck,pydata/bottleneck,kwgoodman/bottleneck,kwgoodman/bottleneck,kwgoodman/bottleneck,pydata/bottleneck