--- a/mercurial/fancyopts.py	Sat May 06 04:51:25 2017 +0530
+++ b/mercurial/fancyopts.py	Fri Feb 10 16:56:29 2017 -0800
@@ -14,7 +14,7 @@
 )
 
 # Set of flags to not apply boolean negation logic on
-nevernegate = set([
+nevernegate = {
     # avoid --no-noninteractive
     'noninteractive',
     # These two flags are special because they cause hg to do one
@@ -22,7 +22,7 @@
     # like aliases anyway.
     'help',
     'version',
-    ])
+}
 
 def gnugetopt(args, options, longoptions):
     """Parse options mostly like getopt.gnu_getopt.