Allow new.function() called with explicit 3rd arg of None, as

documented, and as is reasonable (since it is optional, but there's
another argument following it that may require you to specify a
value).  This solves SF bug 121887.

Modules/newmodule.c

@@ -70,12 +70,17 @@ new_function(PyObject* unused, PyObject* args)
 	PyObject* defaults = Py_None;
 	PyFunctionObject* newfunc;
 
-	if (!PyArg_ParseTuple(args, "O!O!|SO!:function",
+	if (!PyArg_ParseTuple(args, "O!O!|OO!:function",
 			      &PyCode_Type, &code,
 			      &PyDict_Type, &globals,
 			      &name,
 			      &PyTuple_Type, &defaults))
 		return NULL;
+	if (name != Py_None && !PyString_Check(name)) {
+		PyErr_SetString(PyExc_TypeError,
+				"arg 3 (name) must be None or string");
+		return NULL;
+	}
 
 	newfunc = (PyFunctionObject *)PyFunction_New(code, globals);
 	if (newfunc == NULL)