diff --git a/Lib/functools.py b/Lib/functools.py
index 1effc08..b2df390 100644
--- a/Lib/functools.py
+++ b/Lib/functools.py
@@ -65,7 +65,6 @@
     return partial(update_wrapper, wrapped=wrapped,
                    assigned=assigned, updated=updated)
 
-_object_defaults = {object.__lt__, object.__le__, object.__gt__, object.__ge__}
 def total_ordering(cls):
     """Class decorator that fills in missing ordering methods"""
     convert = {
@@ -82,9 +81,8 @@
                    ('__gt__', lambda self, other: not other >= self),
                    ('__lt__', lambda self, other: not self >= other)]
     }
-    roots = set(dir(cls)) & set(convert)
-    # Remove default comparison operations defined on object.
-    roots -= {meth for meth in roots if getattr(cls, meth) in _object_defaults}
+    # Find comparisons not inherited from object.
+    roots = [op for op in convert if getattr(cls, op) is not getattr(object, op)]
     if not roots:
         raise ValueError('must define at least one ordering operation: < > <= >=')
     root = max(roots)       # prefer __lt__ to __le__ to __gt__ to __ge__