--- a/bench.py	Sat May 02 01:52:26 2015 +0800
+++ b/bench.py	Sat May 02 02:56:30 2015 +0800
@@ -25,7 +25,7 @@
 
 
 parser = ArgumentParser(description='Benchmark revisions and put results in the db.')
-parser.add_argument('revsets', metavar='REVSET', default='last(all(), 120)', nargs='*', help='update these revisions')
+parser.add_argument('revsets', metavar='REVSET', default=('last(all(), 120)',), nargs='*', help='update these revisions')
 parser.add_argument('--retry', action='store_true', help='try and reduce existing timings')