3.10 is the floor: the implementations use X | None in annotations that are evaluated at runtime.

This repository is teaching material. Every problem is a self-contained command-line program using only the standard library — nothing here opens a socket, reads a credential, or runs untrusted input. The realistic issues are therefore bugs in the designs themselves rather than vulnerabilities, and those are best raised as issues.

Do not copy these implementations into production systems without review. They are written to make a design idea legible, and several deliberately leave out concerns a real system needs — concurrency above all. Each problem's README lists what it omits under "Follow-ups".

If you do find something genuinely security-relevant, or a problem with the repository's CI or dependencies:

• Open an issue, or
• Email Abhay Paswan — work.abhaypaswan@gmail.com