--- a/mercurial/exthelper.py	Sun Oct 06 19:25:18 2019 -0400
+++ b/mercurial/exthelper.py	Mon Oct 07 00:04:04 2019 -0400
@@ -106,7 +106,7 @@
         self._extcommandwrappers.extend(other._extcommandwrappers)
         self._functionwrappers.extend(other._functionwrappers)
         self.cmdtable.update(other.cmdtable)
-        for section, items in other.configtable.iteritems():
+        for section, items in pycompat.iteritems(other.configtable):
             if section in self.configtable:
                 self.configtable[section].update(items)
             else: