Merge pull request #1338 from collective/1244-attry.categories_proper… #3021

	name: Check code style with ruff
	on: [push, pull_request]
	jobs:
	ruff:
	runs-on: ubuntu-latest
	env:
	MESSAGE: \|
	Your code is not formatted!
	Please set up your development environment and run the formatting command.
	https://icalendar.readthedocs.io/en/stable/contribute/development.html#code-format
	steps:
	- uses: actions/checkout@v6
	- name: Set up Python
	uses: actions/setup-python@v6
	with:
	python-version: 3.14
	cache: pip
	- name: Install dependencies
	run: \|
	python -m pip install --upgrade pip
	pip install . --group formatting
	sudo apt install -y git-delta
	- name: Run the ruff formatter to change files
	run: ruff format .
	- name: Fail if we detect any changes on the file system
	run: \|
	git diff \| delta --light --keep-plus-minus-markers
	if ! git diff --exit-code --quiet; then
	echo "$MESSAGE"
	exit 1;
	fi
	env:
	FORCE_COLOR: '1'
	- name: Run ruff checks on the files
	run: \|
	if ! ruff check; then
	echo "$MESSAGE"
	exit 1;
	fi

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