In other parts of the code, I try to avoid using `dirnameForValue` except when generating the path to create. I know this is perfectly safe, but it does make an assumption about how the FS internals create the path--that `dirnameForValue` is used--and requires exposing the method. Because the path exists at this point, I'd rather pass a `Path` and use `SEP.split(path.toString())` to generate the list.