--- a/mercurial/transaction.py	Sun Oct 06 19:25:18 2019 -0400
+++ b/mercurial/transaction.py	Mon Oct 07 00:04:04 2019 -0400
@@ -355,7 +355,7 @@
     def _generatefiles(self, suffix=b'', group=gengroupall):
         # write files registered for generation
         any = False
-        for id, entry in sorted(self._filegenerators.iteritems()):
+        for id, entry in sorted(pycompat.iteritems(self._filegenerators)):
             any = True
             order, filenames, genfunc, location = entry