--- a/mercurial/upgrade.py	Sat Dec 15 16:28:29 2018 +0900
+++ b/mercurial/upgrade.py	Thu Dec 13 23:20:28 2018 -0800
@@ -142,7 +142,7 @@
         return self.name == other.name
 
     def __ne__(self, other):
-        return not self == other
+        return not (self == other)
 
     def __hash__(self):
         return hash(self.name)