Thanks for this repo! I have used it to solve one of the Google foobar challenges.

I would like to suggest some improvements to the code in this repo, I can send individual PRs for each point or one combined for multiple:

1. Small auxiliary stuff like better .gitignore and other config files for commonly used tools: .gitignore, config files.
2. Running commonly used code formatters: Black, isort, pyupgrade.
3. Adding type hints.
4. Removing custom copy and just using built-in Python module: see here.
5. Simplifying Blossom id code, there's no need for class variable to track id, built-in id on instance is enough: one, two.
6. Changed constructors for Forest, Matching for easier usage.
7. Simplify augemnting Matching, there's no need to create a copy in our algorithm, we can modify the callee directly: see here.
8. Simplify adding an edge to the Forest, there's only one possible path in the blossom algorithm that can happen: see here.
9. Somewhat simplify finding bottom up path to the root: see here.
10. Simplify finding Blossom in the Forest: see here. I should note that I wrote this code last year so I'm a bit rusty on it but I'm pretty sure it's still correct (all tests are passing and I passed foobar tests as well).
11. Other small changes here and there leveraging Python idioms: see here.