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  One of the many things that I learned at DEF CON a few weeks ago is about Python Class Pollution and how a harmless snippet like the one below can cause a huge issue if an attacker controls it!

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  I had a bit of a heart attack this morning when we noticed that my Grok 4.6 benchmark experiment using Amazon Bedrock would cost $28,044.59 instead of ~$28.00 that I was expecting 😱

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  PyCon Portugal continues to be my favorite PyCon. This year it was in Aveiro (a better Venice 😉) and we had a blast! I enjoyed giving my talk on lazy imports, but the best part was meeting new people and catching up with friends. Looking forward to it again next year!

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  🐍 Python Lisbon Meetup is tomorrow! 🎤 Talk by @mathsppblog ⚡ Lightning talks 🍻 Socializing 📍 IST, Sala Multiusos, Torre Norte (new room, not the Pavilhão de Matemática!) 🕖 Thu, 1 Oct, 19:00 RSVP links below 👇

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  Python 3.15 has been released 🎉 Grab it while it's fresh 😉 https://www.python.org/downloads/release/python-3150/

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  Make sure to always reuse your botoclients. Initializing a fresh one on each task has A LOT of overhead!

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  Oh, I didn’t know GitHub doesn’t have pagination in the Commits tab of a pull request. 😅

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  The Claude usage page is very confusing. Since Sonnet has a separate bar I thought I'd be able to switch to it after I max out Opus, but nope. Of course this all makes sense if you actually read the tooltip/labels but who does that today anyway? 😅

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  A bug that survived 15 years of upgrades. One of my servers lost DNS after every reboot. ping 8.8.8.8 worked; ping https://google.com didn't resolve. I'd been "fixing" it by hand-editing /etc/resolv.conf, which, of course, was reset on the next boot. 🙈 Turned out to be a config from 2010. I finally debugged it properly with Claude. https://blog.pecar.me/the-15-year-old-iptables-rule-that-broke-my-dns

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  After 9 meetups full of talks, lightning talks, and even lightning turtles, it's time for the Python Lisbon Meetup to take it easy. Join us at Linha d'Água on Thursday to relax and enjoy the summer in Lisbon with Python friends 🐢 https://www.meetup.com/python-lisbon-meetup/events/315420890/

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  Today I migrated some Go code to Python and made it 590x FASTER 😎

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  We reviewed 4,978 mypy runs in our Django app: • 4,731 green • 246 failed Of the 246 failures: • 173 false positives • 73 real issues • 39 caught only by mypy and no other check! Some noise, but it prevented real bugs from reaching production. 🎉

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  I asked Claude to come up with writing guidelines based on my blog posts: > A few things I deliberately did not encode as guidelines: the frequent typos (characteristic of your fast publishing cadence) 88 blog post in 14 years is not fast publishing cadence 😅

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  Quite a way to start a Monday 😅

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  We benchmarked 15 models for triaging vulnerabilities. * Kimi K3 came out on top but marked a true positive as a false positive ☠️ * Opus 5 refused to give a verdict on 11 vulnerabilities * Sonnet 5 and Luna outperformed Terra and Sol Full post 👇 https://www.fencer.dev/blog/llm-triage-sast-false-positives

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  My dog kept me in Zone 2 for 3kms. Then I had to drop him off and immediately made bad decisions. 💛

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  Everyone’s favorite web framework is now also in the gelato business 🤤

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  With all the supply chain attacks going around, we have to be very careful about how we update our dependencies. I've written a full blog post about it, but here is the TLDR: 1. Pin to hashes, not just versions 2. Automate the updates 3. Use dependency cooldowns https://blog.pecar.me/how-to-safely-update-your-dependencies/

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  I've finished #adventofcode 2025 and this is the first year that I managed to get all solutions under 100ms ⚡ All but two are under 10ms. Not bad for the slowest popular language out there 🐍, although I did have to use numpy a few times.

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  I wrote a blog post about this year's Advent of Code. I had a blast and I am already looking forward to 2026! * All my Python solutions were under 1s using pure Python and 100ms with a little help from mypy/scipy • The AoC community is the best ❤️ https://blog.pecar.me/advent-of-code-2025

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  New board!

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  Hey all! It's almost time for the next Python Lisbon Meetup! 🐍 On Thursday, pyctrl will be talking about exceptions. We'll cover the origin of exceptions, their usage in OOP, how best to manage them, and more. It's going to be exceptional! 💎

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  Like pretty much everyone with a static blog site in the last 6 months, I asked Claude to migrate it to a different static site generator. Here's a blog post about it, along with some of my general thoughts on agentic code. https://blog.pecar.me/agentic-adventures/

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  I wrote a blog post about some of the options for adding type checking to your Django project! Historically, Django projects have been tough to type-check, but the future feels bright, especially if PEP 827 gets accepted! https://blog.pecar.me/typing-your-django-project-in-2026/

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  Can't wait for lazy imports in Python 3.15! I spent a bunch of time and tokens over the weekend inlining heavy imports so that they don't get loaded during initial start of a Django app. The `https://manage.py check` command is now 3.8x faster (9.45s down to 2.48s).

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  I wrote a post on how we tracked down slow imports in our Django app, fixed them by making imports lazy, and added a lint check to prevent regressions. Now I’m waiting for Python 3.15 to make all of this easier! 🚀 https://blog.pecar.me/speeding-up-django-startup-times-with-lazy-imports/

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  I'll be giving a talk about lazy imports at the next Python Lisbon Meetup! See you there? 😀 https://www.meetup.com/python-lisbon-meetup/events/313903112/?eventOrigin=home_next_event_you_are_attending

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  Another Python Lisbon Meetup in the books! Looking forward to the next one on May 7 👀

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  With recent Python supply chain attacks (Trivy/LiteLLM), it’s worth mentioning uv’s `exclude-newer = "x days"` config. It forces uv to only installs packages published more than x days ago, reducing risks since problematic packages should be yanked by then. https://docs.astral.sh/uv/reference/settings/#exclude-newer