convert shebang lines: python -> python3
diff --git a/Demo/scripts/primes.py b/Demo/scripts/primes.py
index d296f0e..c994623 100755
--- a/Demo/scripts/primes.py
+++ b/Demo/scripts/primes.py
@@ -1,4 +1,4 @@
-#! /usr/bin/env python
+#! /usr/bin/env python3
 
 # Print prime numbers in a given range