diff --git a/docs/lab/serve.py b/docs/lab/serve.py
index e0dddebdf..5af9d393e 100755
--- a/docs/lab/serve.py
+++ b/docs/lab/serve.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 from __future__ import print_function, absolute_import
 import os, sys
 import signal