convert shebang lines: python -> python3
diff --git a/Demo/turtle/turtleDemo.py b/Demo/turtle/turtleDemo.py
index 36bf15c..b5b99c0 100644
--- a/Demo/turtle/turtleDemo.py
+++ b/Demo/turtle/turtleDemo.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/env python3
 import sys
 import os