diff --git a/tools/thread_utils.py b/tools/thread_utils.py
index 28fd348..2550ee3 100755
--- a/tools/thread_utils.py
+++ b/tools/thread_utils.py
@@ -113,4 +113,5 @@
 def print_thread(msg, worker_id):
   if worker_id is None:
     print(msg)
-  print('WORKER %s: %s' % (worker_id, msg))
\ No newline at end of file
+  else:
+    print('WORKER %s: %s' % (worker_id, msg))
\ No newline at end of file