afni.nimh.nih.gov

I had been using a little thing I brewed up, but unless you're doing something nifti can't handle (like complicated slice timings), it's probably easier to convert to nifti and use nibabel. If you want it, though, here's what I had before I threw it out and started using nibabel:
[brainimaging.waisman.wisc.edu] (Be aware that this is python3; you might need to backport it.)

ijs