diff --git a/bin/obmc_ser_num b/bin/obmc_ser_num
index ba620c8..4057316 100755
--- a/bin/obmc_ser_num
+++ b/bin/obmc_ser_num
@@ -11,9 +11,9 @@
 save_path_0 = sys.path[0]
 del sys.path[0]
 
-from gen_arg import *
-from gen_print import *
-from gen_valid import *
+from gen_arg import *     # NOQA
+from gen_print import *   # NOQA
+from gen_valid import *   # NOQA
 
 # Restore sys.path[0].
 sys.path.insert(0, save_path_0)