PR 11524 performs the same kind of changes as PR 11520, but for handwritten code (only if this causes noticeable speed up). Also iter() is now use the fast call convention.

$ ./python -m timeit "iter(())"
Unpatched:  5000000 loops, best of 5: 82.8 nsec per loop
Patched:    5000000 loops, best of 5: 56.3 nsec per loop

$ ./python -m timeit -s "it = iter([])" "next(it, None)"
Unpatched:  5000000 loops, best of 5: 54.1 nsec per loop
Patched:    5000000 loops, best of 5: 44.9 nsec per loop

$ ./python -m timeit "getattr(1, 'numerator')"
Unpatched:  5000000 loops, best of 5: 63.6 nsec per loop
Patched:    5000000 loops, best of 5: 57.5 nsec per loop

$ ./python -m timeit -s "from operator import attrgetter; f = attrgetter('numerator')" "f(1)"
Unpatched:  5000000 loops, best of 5: 64.1 nsec per loop
Patched:    5000000 loops, best of 5: 56.8 nsec per loop

$ ./python -m timeit -s "from operator import methodcaller; f = methodcaller('conjugate')" "f(1)"
Unpatched:  5000000 loops, best of 5: 79.5 nsec per loop
Patched:    5000000 loops, best of 5: 74.1 nsec per loop

It is possible to speed up also many math methods and maybe some contextvar and hamt methods, but this is for other issues.