🎉 What’s new in 4.0

Version 4.0 is a modernization release: the public helpers you already rely on are unchanged, but the package underneath is faster to import, stricter about types, and built with a modern toolchain.

The authoritative, per-release changelog lives on the GitHub releases page. The highlights:

🪶 Lazy imports

import python_utils no longer eagerly imports its submodules. Thanks to PEP 562 lazy loading, nothing is imported until first access — notably asyncio and typing_extensions stay out of the import graph until you use a helper that needs them. See the performance guide.

🎯 Strict typing on three checkers

The codebase is verified in strict mode by mypy, basedpyright and pyrefly, and ships py.typed so your own type checker picks up the annotations. Coverage remains at 100%.

🧰 Modern build & tooling

  • Built with the uv_build backend.

  • Linted and formatted with ruff.

  • Git hooks via lefthook.

  • A tox matrix across supported interpreters, with split GitHub Actions CI and PyPI Trusted Publishing.

  • The source distribution ships the test suite and tox.ini, so downstream packagers can build and test from the sdist.

🐍 Supported Python versions

Python 3.10+ is supported, and the package is tested against current CPython releases as well as PyPI.

Handy modules worth a fresh look

  • Async helpers — acount, abatcher, and the timeout/stall detectors.

  • Smart containers — CastedDict, LazyCastedDict, UniqueList, SliceableDeque.

For anything not listed here, consult the release notes for the exact version you’re upgrading from.