custom model registration fails inside of hub/__init__.py due to __pycache__

[outtanames]

When registering custom models with the new yaml flow, module_exec fails to to find module attribute corresponding to the class name. This appears to be due to the __pycache__ storing old/invalid module specs. Need a way to clear out the cache or skip it entirely when registering these models.

[outtanames]

Workaround is to delete the cache when this occurs, but not an easy fix given that it might occur inside the nos container.