Validation of forms

Can anyone recommend a pre-written validation library, suitable for use with form data? I’m not particularly happy with the validation routine in Simon Willison’s FormProcessor class, as it’s just one method within the class - I’d like it to be a separate class as I believe this would enforce the separation better.

*Update (2003/09/04):* Here’s some “Python form validation solutions”:http://toulouse.amber.org/archives/2003/09/03/python_form_and_validation_kits.html as a reference.