No one use ('sth' in session) in webpy's session? Classic-style class will call getattr method if contains method does not exist, but new-style class will call getitem.
Besides, I really think python's import method is very bad, almost I must use import(modname, None, None, ['']) whenever I use it. In webpy's application.py, the reload_mapping method shoule also use import(modname, None, None, ['']) instead of just import(modname).
Anymore, I think memoize in utils.py should be replaced with function, because current implementation in fact makes sth slower.
By the way, is there any components for webpy? webpy is earlier than flask, but component is fewer!