I'm developing a new product for a Zope 2.9.7 site (no CMF). I'd like to use Zope 3 technologies for this product. I've been looking around for a few days, most of what I see describes development for Zope 3, or Five in the context of Plone. Is there a tutorial or a product I can reference that describes how to build a few simple content types "the Zope 3 way" in Zope 2?