I'm +0.
It would certainly be fun, but I'm not so sure about the "profit" part.
The main usage of the scheduler API is for real-time policies, and I
somehow doubt Python is commonly used in this area (but I could be
wrong).
Furthermore, the same functionality can be easily achieved with
schedtool/taskset.

Concerning the patch, I think that several constants ought to be
guarded by #ifdef's: only SCHED_(OTHER|FIFO|RR) are required by POSIX:
the other are Linux-specific (also, SCHED_BATCH, SCHED_IDLE and
SCHED_RESET_ON_FORK are only defined in recent Linux kernels, older
libcs probably don't define them).