library code for multiple python functions?

Suppose we have multiple functions that would share common, library code -- I'm sure this is a very common situation.

I currently ended up writing a minimal python project inside "lib" (the python package is also, inaptly, named `lib` -- apologies). I've ended up with a structure similar to the following:
```
.
├── .env
├── .gitignore
├── lib
│   └── lib
│   ├── pyproject.toml
│   └── src
│   └── lib
│   ├── __init__.py
│   ├── db.py
│   └── rest.py
├── packages
│   └── servers
│   ├── get_servers
│   │   ├── __deployer__.zip
│   │   ├── __main__.py
│   │   ├── build.sh
│   │   └── virtualenv
│   └── put_server
│   ├── __deployer__.zip
│   ├── __main__.py
│   ├── build.sh
│   └── virtualenv
└── project.yml
```

and each function's build.sh roughly doing
```
virtualenv --without-pip virtualenv
pip install ../../../lib/lib --target virtualenv/lib/python3.9/site-packages
```

Is there a better way? Could you add an example (or alter an existing example) with how to best achieve this?