Sorry for ghosting. I've worked with this more and I don't think it's a good pattern. Specifically, the python extension for the serverless framework implements similar behavior, except that it will go into nested modules, but not into nested python objects. I think this library handles that.

Either way I've found that a more standard approach just forwards the invocation from a handler.py type file to the desired method, if anyone is interested in doing something similar with grouping lambdas' handling logic in a python class.