There is one handler which corresponds to the app itself, whereas all other handlers correspond to some “portion” of the app. This main app handler’s primary purpose is to:
provide a common interface for obtaining all other handlers
provide some “global” methods, e.g. for rendering date/time values
You can override the main app handler, with config like:
app.handler = poser.app:PoserAppHandler
Of course that must point to a valid
AppHandler class, which you
probably must create.
rattail.app.AppHandler which is the default
and base class.