First, I would like to thank you for the nice codecov. io project
PR on GitHub is here Remove redundant code by hexagonrecursion · Pull Request #334 · twisted/towncrier · GitHub
Here is this diff Code coverage done right.
There is a line of unused code that was removed.
Codecov delta is reporting a decrease in coverage.
I think that this is bug as that line was removed since it was doing nothing. it was just a useless assignment without any side effects.
I am reporting this as maybe this is a simple example that can help improve your algorithm.
Regards