How to write and publish a Python package to PyPI

I wanted to publish my Scrapy download handler to PyPi - UV made it incredibly easy. Here's how. At some point, every scraping developer writes the same middleware twice. The first time is in project A. It works well, so when project B comes along you copy it across. Then project C. Then a colleague asks for it. You email them the file. They make changes. Now there are four versions of the same code living in four different repositories, diverging slowly, none of them getting each other's bug fi