> Although I think that at least one function could be useful to the users :
> concat_niimgs. When talking with Michael about nisl, he told me that he may
> need this kind of function (he has several 4D nifti files taht he wants to
> concatenate).

That's a good point. We definitely want this function with a non-private
import path. I'd still like a better name than 'utils'. Any suggestions?