--- a/mercurial/help.py	Wed Jul 19 13:17:49 2017 -0700
+++ b/mercurial/help.py	Wed Apr 03 11:21:27 2019 -0700
@@ -748,7 +748,7 @@
                 ct = mod.cmdtable
             except AttributeError:
                 ct = {}
-            modcmds = set([c.partition('|')[0] for c in ct])
+            modcmds = {c.partition('|')[0] for c in ct}
             rst.extend(helplist(modcmds.__contains__))
         else:
             rst.append(_("(use 'hg help extensions' for information on enabling"