Hi all, Just a reminder that PEP 576 still exists as a lightweight alternative to PEP 575/580. It achieves the same goals as PEP 580 but is much smaller. https://github.com/markshannon/pep-576 Unless there is a big rush, I would like to do some experiments as to whether the new calling convention should be typedef (*callptr)(PyObject *func, PyObject *const *stack, Py_ssize_t nargs, PyObject *kwnames); or whether the increased generality of: typedef (*callptr)(PyObject *func, PyObject *const *stack, Py_ssize_t nargs, PyObject *kwnames, PyTupleObject *starargs, PyObject *kwdict); is a worthwhile enhancement. An implementation can be found here: https://github.com/python/cpython/compare/master...markshannon:pep-576-minim... Cheers, Mark.