convert shebang lines: python -> python3
diff --git a/Tools/scripts/classfix.py b/Tools/scripts/classfix.py
index 0cd1e49..971d1bd 100755
--- a/Tools/scripts/classfix.py
+++ b/Tools/scripts/classfix.py
@@ -1,4 +1,4 @@
-#! /usr/bin/env python
+#! /usr/bin/env python3
 
 # This script is obsolete -- it is kept for historical purposes only.
 #