BREAKING NEWS!
The engineer who built Claude Code from scratch just released a 28-minute video that's pure gold: how to write prompts that deliver ridiculously good results.
I've seen $300 courses that don't even come close to what he explains in the first 10 minutes.
CLAUDE.md files, memory shortcuts, parallel sessions, and prompting patterns that almost no one uses...
All in one single video. Completely free. No fluff.
Whether you're a developer, just starting, or have already been using Claude for months, this changes the game for you starting today.
Save. Watch. Share.
12/12 — Master Python Strings 🐍🔥
If you understand:
✅ Indexing
✅ Negative indexing
✅ Slicing
✅ Step slicing
✅ Concatenation
✅ String methods
✅ f-Strings
✅ Immutability
you already have a strong foundation for working with text in Python.
Save this thread for revision. 🔖
Learn → Practice → Experiment → Quiz
Follow @clcoding for more Python tutorials, coding tips, and challenges. 🚀
The worst bug isn't the one that crashes. It's the one where your method returns "Success", and three systems disagree about what just happened.
Classic version: customer gets charged, the payment provider has the money, but your SaveChanges() threw right after. The order rolls back to draft. The user gets a "Payment failed, please retry" email. One click, and every subsystem now tells a different story.
The trap is that a use case *looks* like a transaction. It sits behind one method call. But the moment it touches more than one system, DB + payment + email, you're dealing with partial failure, and there's no single "handle errors properly" rule that saves you.
What actually helps is classifying every side effect first:
→ Transactional (DB inserts/updates, in-process domain events) - commit these LAST, after the external work has succeeded.
→ External but reversible (charge → refund, reserve → release) - make it idempotent (an idempotency key so a retry is a no-op) or compensate via an event.
→ External and irreversible (emails, webhooks, SMS) - get them OUT of the use case entirely. Raise a domain event, let the Outbox dispatch it after commit. If the transaction never commits, the email never escapes the DB.
The one thing you never do: swallow the failure to make the method "look successful." The symptom leaves your logs, the money stays gone, and the retry double-charges.
The mental model that fixed this for me: a use case is a unit of *intent*, not a unit of *atomicity*. Most event-driven production bugs I've debugged come down to a method that lied about whether it actually succeeded.
I break down production #dotnet patterns like this every Monday for 20,000+ engineers → https://t.co/gI46R2Kc0c
How do you handle the charge-succeeds-but-commit-fails case in your services?
@PythonPr Very offensive image towards Seniors. Don't they analyze everything by themselve, AI can do anything for Juniors but not the skill and logic development like seniors.