[google-appengine] Google app engine unable to use python 3

I've following the instruction in: https://cloud.google.com/appengine/docs/flexible/python/quickstart But when I execute "python" the version number still show 2.7.9, I've checked the app.yaml, it already set the python_version: 3 -- You received this message because you are subscribed to th

[google-appengine] Google app engine unable to use python 3

I've following the instruction in: https://cloud.google.com/appengine/docs/flexible/python/quickstart But when I execute "python" the version number still show 2.7.9, I've checked the app.yaml, it already set the python_version: 3 -- You received this message because you are subscribed to th