I'll push my changes up shortly, but by doing ```a[~a.mask].data``` as is currently done, the code implicitly moves from n-dimensional arrays to 1d. This change ensures 0d arrays work the same way along with 1d, 2d, etc. I agree it's not especially intuitive, but at least it's consistent. I've added a docstring to hopefully make it clear that this helper function always returns a 1d ndarray. Take a look at my change and let me know if you feel it's still objectionable.