It is a pain, but then again, we have a mostly working system, so I think it doesn't hurt *that* much to just put in a hack for a few corner cases. Perhaps mine is not so bad?  At least it is extensible. Alternatively, we could just replace
```
if hasattr(u, key):
    names[key] = getattr(u, key)
```
and not unreasonably assume that nobody will ever have a fits file with units of `dbyte`.