diff -r 73dfc72704b6 -r d170f59f6f55 mercurial/commands.py
--- a/mercurial/commands.py	Mon Jun 26 09:37:16 2017 +0900
+++ b/mercurial/commands.py	Sat Jun 24 19:55:01 2017 +0530
@@ -944,12 +944,11 @@
 
           hg book -f @
     '''
-    opts = pycompat.byteskwargs(opts)
-    force = opts.get('force')
-    rev = opts.get('rev')
-    delete = opts.get('delete')
-    rename = opts.get('rename')
-    inactive = opts.get('inactive')
+    force = opts.get(r'force')
+    rev = opts.get(r'rev')
+    delete = opts.get(r'delete')
+    rename = opts.get(r'rename')
+    inactive = opts.get(r'inactive')
 
     if delete and rename:
         raise error.Abort(_("--delete and --rename are incompatible"))