Nevow (pronounced as the French "nouveau", or "noo-voh") is a web application
construction kit written in Python. It is designed to allow the programmer to
express as much of the view logic as desired in Python, and includes a pure
Python XML expression syntax named stan to facilitate this. However it also
provides rich support for designer-edited templates, using a very small XML
attribute language to provide bi-directional template manipulation capability.

Nevow also includes formless, a declarative syntax for specifying the types of
method parameters and exposing these methods to the web. Forms can be rendered
automatically, and form posts will be validated and input coerced, rendering
error pages if appropriate. Once a form post has validated successfully, the
method will be called with the coerced values.

See also: https://github.com/twisted/nevow