diff --git a/offlineimap/utils/stacktrace.py b/offlineimap/utils/stacktrace.py
index ba6bf4f..eacd5e8 100644
--- a/offlineimap/utils/stacktrace.py
+++ b/offlineimap/utils/stacktrace.py
@@ -1,6 +1,8 @@
-# Copyright 2013 Eygene A. Ryabinkin
-# Functions to perform stack tracing (for multithreaded programs
-# as well as for single-threaded ones).
+"""
+Copyright 2013 Eygene A. Ryabinkin
+Functions to perform stack tracing (for multithreaded programs
+as well as for single-threaded ones).
+"""
 
 import sys
 import threading