--- a/rollbot.py	Fri Jun 03 11:36:03 2016 +0800
+++ b/rollbot.py	Fri Jun 24 07:36:35 2016 +0800
@@ -205,8 +205,9 @@
     group.add_argument('--prefix', help='command prefix (default: !)')
 
     group = parser.add_mutually_exclusive_group()
-    group.add_argument('-q', '--quiet', help='set logging to ERROR', action='store_const', dest='loglevel', const=logging.ERROR, default=logging.INFO)
-    group.add_argument('-d', '--debug', help='set logging to DEBUG', action='store_const', dest='loglevel', const=logging.DEBUG, default=logging.INFO)
+    extra = dict(action='store_const', dest='loglevel', default=logging.INFO)
+    group.add_argument('-q', '--quiet', help='set logging to ERROR', const=logging.ERROR, **extra)
+    group.add_argument('-d', '--debug', help='set logging to DEBUG', const=logging.DEBUG, **extra)
 
     args = parser.parse_args()