Comment by tamnd
My biggest inspiration for this project, though, is The Art of Computer Programming (TAOCP), that level of depth and precision is the ultimate goal. I'm also planning to include formal proofs of all algorithms in Lean, though that could easily turn into a 10-year project.
Python probably is not suitable for any project that you want to retain value for 10 years or more; the community has a policy against maintaining backward compatibility.