Indentation here is funny.

Also, it'd be nice if we could avoid duplicating the whole function body just to add this one check -- anyone more familiar with the @@ templating stuff have an opinion on whether that's doable? I guess we could `#define NO_CHECK_EXACT(a) 0` and then use it as the `PYCHECKEXACT`/`PYEXTRACTCTYPE` functions for the types which don't have python scalars?