Captcha solution which can be used with App Engine?

Is there a simple captcha solution which can be easily integrated with a form deployed using Google App Engine? I am using Python.开发者_如何学C

Recaptcha. It does work with Python.

http://www.google.com/recaptcha

http://code.google.com/apis/recaptcha/docs/otherplatforms.html

http://pypi.python.org/pypi/recaptcha-client

I didn't test, but I guess this can work: http://daily.profeth.de/2008/04/using-recaptcha-with-google-app-engine.html, he use reCaptcha