-#! /usr/bin/env python
-# Copyright (c) 2013, 2014, 2015 Nicira, Inc.
+#! /usr/bin/env python3
+# Copyright (c) 2013, 2014, 2015, 2020 Nicira, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.