SF bug #699934: Obscure error message

mwh pointed out that the error message did not
make sense if obtained by rearranging the bases.

Lib/test/test_descr.py

@@ -1062,9 +1062,8 @@ def consistency_with_epg():
           (EditableScrollablePane, ScrollablePane, EditablePane,
            Pane, ScrollingMixin, EditingMixin, object))
 
-mro_err_msg = """Cannot create class.The superclasses have conflicting
-inheritance trees which leave the method resolution order (MRO)
-undefined for bases """
+mro_err_msg = """Cannot create a consistent method resolution
+order (MRO) for bases """
 
 def mro_disagreement():
     if verbose: print "Testing error messages for MRO disagreement..."

Objects/typeobject.c

@@ -1082,10 +1082,8 @@ set_mro_error(PyObject *to_merge, int *remain)
 	}
 	n = PyDict_Size(set);
 
-	off = PyOS_snprintf(buf, sizeof(buf), "Cannot create class.\
-The superclasses have conflicting\n\
-inheritance trees which leave the method resolution order (MRO)\n\
-undefined for bases");
+	off = PyOS_snprintf(buf, sizeof(buf), "Cannot create a \
+consistent method resolution\norder (MRO) for bases");
 	i = 0;
 	while (PyDict_Next(set, &i, &k, &v) && off < sizeof(buf)) {
 		PyObject *name = class_name(k);