SF bug [#466173] unpack TypeError unclear
Replaced 3 instances of "iter() of non-sequence" with
"iteration over non-sequence".
Restored "unpack non-sequence" for stuff like "a, b = 1".
diff --git a/Objects/classobject.c b/Objects/classobject.c
index df10aa2..cef1894 100644
--- a/Objects/classobject.c
+++ b/Objects/classobject.c
@@ -1839,7 +1839,7 @@
 	}
 	PyErr_Clear();
 	if ((func = instance_getattr(self, getitemstr)) == NULL) {
-		PyErr_SetString(PyExc_TypeError, "iter() of non-sequence");
+		PyErr_SetString(PyExc_TypeError, "iteration over non-sequence");
 		return NULL;
 	}
 	Py_DECREF(func);