build VS sheet-python

If it's pure Python, the only packaging file you need is `pyproject.toml`. You can fill that file with packaging metadata per PEP 518 and PEP 621, including using modern build tooling like flit[1] for the build backend and build[2] for the frontend.

With that, you entire package build (for all distribution types) should be reducible to `python -m build`. Here's an example of a full project doing everything with just `pyproject.toml`[3] (FD: my project).

[1]: https://github.com/pypa/flit

[2]: https://github.com/pypa/build

[3]: https://github.com/pypa/pip-audit

RE the dislike of a "third-party tool", what do you mean by this? All the major tools for packaging in Python are under the PyPA, e.g. - twine - build - hatch

building wheels/sdists to upload or install: build

python3 setup.py sdist bdist_wheel - no need for an sdist when building wheels, also I'd recommend using pypa/build instead.

The first step is to turn the internal package into a wheel (a *.whl file). We can use the build tool for this purpose. After installing build with pip we can run it as follows:

Shouldn't https://github.com/pypa/build help? I don't think it has enough features yet but I was under the impression that was the distro solution.