如何更改用于部署到GAE的帐户?

Im having a problem where I used one account to deploy to GAE through terminal and GAE SDK, i.e goapp deploy. Not at a later point I need to deploy to another account but I dont understand how to change this in terminal? How do I trigger a new login to happen?

I read this question: How to switch google app engine account to deploy applications? but I dont get it to work either. I write the --email=bla@gmail.com flag but get the error message:

flag provided but not defined: -email

Am I using the --email flag wrong or maybe wrong parameters?

Use the --no_cookies flag, e.g.:

python2.7 /path/to/google_appengine/appcfg.py --no_cookies update myapp

--no_cookies

Do not store the administrator sign-in credentials as a cookie; prompt for a password every time. This flag will bring up a prompt for your email address as well.