You're adding type hints to your Python code, your editor is happy, autocomplete is working great. But then you switch tools and suddenly there are red squiggles everywhere. Who decides what a float annotation actually means? Or whether passing None where an int is expected should be an error? It turns out there's a five-person council dedicated to exactly these questions -- and two brand-new Rust-based type checkers are raising the bar. On this episode, I sit down with three members of the Python Typing Council -- Jelle Zijlstra, Rebecca Chen, and Carl Meyer -- to learn how the type system is governed, where the spec and the type checkers agree and disagree, and get the council's official advice on how much typing is just enough. 
 
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<h2 class="links-heading mb-4">Links from the show</h2>
<div>Guests 
Carl Meyer: <a href="https://github.com/carljm?featured_on=talkpython" target="_blank" >github.com</a> 
Jelle Zijlstra: <a href="https://jellezijlstra.github.io?featured_on=talkpython" target="_blank" >jellezijlstra.github.io</a> 
Rebecca Chen: <a href="https://github.com/rchen152?featured_on=talkpython" target="_blank" >github.com</a> 
 
Typing Council: <a href="https://github.com/python/typing-council?tab=readme-ov-file&featured_on=talkpython" target="_blank" >github.com</a> 
typing.python.org: <a href="http://typing.python.org?featured_on=talkpython" target="_blank" >typing.python.org</a> 
details here: <a href="https://github.com/python/typing-council?tab=readme-ov-file#decision-making-considerations" target="_blank" >github.com</a> 
ty: <a href="https://docs.astral.sh/ty/?featured_on=talkpython" target="_blank" >docs.astral.sh</a> 
pyrefly: <a href="https://pyrefly.org?featured_on=talkpython" target="_blank" >pyrefly.org</a> 
conformance test suite project: <a href="https://github.com/python/typing/tree/main/conformance?featured_on=talkpython" target="_blank" >github.com</a> 
typeshed: <a href="https://github.com/python/typeshed?featured_on=talkpython" target="_blank" >github.com</a> 
Stub files: <a href="https://mypy.readthedocs.io/en/stable/stubs.html?featured_on=talkpython" target="_blank" >mypy.readthedocs.io</a> 
Pydantic: <a href="http://pydantic.dev?featured_on=talkpython" target="_blank" >pydantic.dev</a> 
Beartype: <a href="https://github.com/beartype/beartype?featured_on=talkpython" target="_blank" >github.com</a> 
TOAD AI: <a href="https://github.com/batrachianai/toad?featured_on=talkpython" target="_blank" >github.com</a> 
PEP 747 – Annotating Type Forms: <a href="https://peps.python.org/pep-0747/?featured_on=talkpython" target="_blank" >peps.python.org</a> 
PEP 724 – Stricter Type Guards: <a href="https://peps.python.org/pep-0724/?featured_on=talkpython" target="_blank" >peps.python.org</a> 
Python Typing Repo (PRs and Issues): <a href="https://github.com/python/typing?featured_on=talkpython" target="_blank" >github.com</a> 
 
Watch this episode on YouTube: <a href="https://www.youtube.com/watch?v=bzh-0FlAmP0" target="_blank" >youtube.com</a> 
Episode #539 deep-dive: <a href="https://talkpython.fm/episodes/show/539/catching-up-with-the-python-typing-council#takeaways-anchor" target="_blank" >talkpython.fm/539</a> 
Episode transcripts: <a href="https://talkpython.fm/episodes/transcript/539/catching-up-with-the-python-typing-council" target="_blank" >talkpython.fm</a> 
 
Theme Song: Developer Rap 
🥁 Served in a Flask 🎸: <a href="https://talkpython.fm/flasksong" target="_blank" >talkpython.fm/flasksong</a> 
 
---== Don't be a stranger ==--- 
YouTube: <a href="https://talkpython.fm/youtube" target="_blank" > youtube.com/@talkpython</a> 
 
Bluesky: <a href="https://bsky.app/profile/talkpython.fm" target="_blank" >@talkpython.fm</a> 
Mastodon: <a href="https://fosstodon.org/web/@talkpython" target="_blank" > @talkpython@fosstodon.org</a> 
X.com: <a href="https://x.com/talkpython" target="_blank" > @talkpython</a> 
 
Michael on Bluesky: <a href="https://bsky.app/profile/mkennedy.codes?featured_on=talkpython" target="_blank" >@mkennedy.codes</a> 
Michael on Mastodon: <a href="https://fosstodon.org/web/@mkennedy" target="_blank" > @mkennedy@fosstodon.org</a> 
Michael on X.com: <a href="https://x.com/mkennedy?featured_on=talkpython" target="_blank" > @mkennedy</a> </div>

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