Add a new private function

PyObject *_PyObject_MakeTpCall(PyObject *callable, PyObject *const *args, Py_ssize_t nargs, PyObject *keywords)

to call "callable" using tp_call, but with arguments given using the FastCallKeywords or FastCallDict convention (both are allowed, see also https://github.com/python/peps/pull/1038).

The code is not new, it's essentially moving the tp_call case out of _PyObject_FastCallKeywords() and _PyObject_FastCallDict().

This was first proposed (as public API under the name PyCall_MakeTpCall) for PEP 590 but it makes sense to do this independently.

I forgot to mention that the idea and first implementation comes from Mark Shannon.

Avoiding the duplication makes sense, but without the rest of PEP 590 it could just be a static function in call.c.

So what are you trying to say? That it *should* be a static function? It most likely won't be a static function after PEP 590 is fully implemented.

Ah, sorry, I didn't get the message through.

I'll merge it with the rest of PEP 590. Adding the symbol doesn't make sense *right* now.

In that case, there is no point a making a separate issue or PR.