Mark Dickinson: no extension module would ever *need* it.  One could
reproduce the functionality with stub intermediary functions, as follows:

PyObject *my_getter_with_context(PyObject *self, void *context) {
  /* ... /
}

PyObject *my_getter_A(PyObject *self) {
  return my_getter_with_context(self, "A");
}


PyObject *my_getter_B(PyObject *self) {
  return my_getter_with_context(self, "B");
}

/* etc. */

The body of Python extension code shows that this facility is rarely
needed.  And folks that need it can roll their own.

It's a minor thing, but I think it's worth doing, if we're willing to
break compatibility in this way.

Anyway, I'm gonna float it on python-dev.