Customizing python package directory layout with setup.py

Suppose I have the following directory structure:

src/
└── python/
    └── generated/
        ├── __init__.py
        ├── a.py
        └── lib/
            ├── __init__.py
            └── b.py

What does my setup.py need to look like in order to create a dist with a directory layout like:

src/
└── python/
    ├── __init__.py
    ├── a.py
    └── lib/
        ├── __init__.py
        └── b.py

The goal is to simply eliminate the generated folder. I've tried endless variations with package_dir and can't get anything produced other than the original directory structure.

from Customizing python package directory layout with setup.py