--- a/hgext/mq.py	Tue Nov 05 12:10:38 2019 -0500
+++ b/hgext/mq.py	Tue Nov 05 08:42:42 2019 -0800
@@ -567,7 +567,7 @@
         return self.seriesguards
 
     def invalidate(self):
-        for a in b'applied fullseries series seriesguards'.split():
+        for a in 'applied fullseries series seriesguards'.split():
             if a in self.__dict__:
                 delattr(self, a)
         self.applieddirty = False