I do get a warning. I think this warning is not specific to line 148 but has something to do with either the boxplot styles or the color argument.

from colorpicker import * items = [ ("item 1", "xkcd:spruce"), ("item 2", "xkcd:dark mint green"), ("item 3", "xkcd:spearmint"), ("item 4", None), ] fig, ax = plt ...