Should you ever work on a Python project to be consumed by the general public, sooner or later you will need to make it available on the Python Package Index (also known as PyPI). And, if you follow the Python Packaging Guide, you will learn about the tool to use for this purpose - Twine. Following the same thread, you might find out about the Test PyPI instance, which would seem like a perfect spot to try out your release on before making it available on the main PyPI repository. Except for one big gotcha...