Don't call len on DataFrame interchange protocol object (#3111) #169

	name: lint

	on: [push, pull_request]

	jobs:
	build:
	runs-on: ubuntu-latest
	name: black-ruff-mypy
	steps:
	- uses: actions/checkout@v3
	- name: Set up Python 3.10
	uses: actions/setup-python@v4
	with:
	python-version: "3.10"
	# Installing all dependencies and not just the linters as mypy needs them for type checking
	- name: Install dependencies
	run: \|
	python -m pip install --upgrade pip
	pip install .[dev]
	- name: Check formatting with black
	run: \|
	black --diff --color .
	black --check .
	- name: Lint with ruff
	run: \|
	ruff check .
	- name: Lint with mypy
	run: \|
	mypy altair tests

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