diff --git a/tools/test/topos/attmpls.py b/tools/test/topos/attmpls.py
index fedcb6c..b72e711 100644
--- a/tools/test/topos/attmpls.py
+++ b/tools/test/topos/attmpls.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 """
 """