Index: Objects/funcobject.c
===================================================================
--- Objects/funcobject.c	(Revision 88058)
+++ Objects/funcobject.c	(Arbeitskopie)
@@ -493,6 +493,13 @@
     PyObject **d, **k;
     Py_ssize_t nk, nd;
 
+    if (!PyFunction_Check(func)) {
+        PyErr_Format(PyExc_TypeError,
+                     "'function' object expected, got '%s' instead",
+                     Py_TYPE(func)->tp_name);
+        return NULL;
+    }
+    
     argdefs = PyFunction_GET_DEFAULTS(func);
     if (argdefs != NULL && PyTuple_Check(argdefs)) {
         d = &PyTuple_GET_ITEM((PyTupleObject *)argdefs, 0);