ci: Restore MPI notebook testing #7173

	name: Flake8

	concurrency:
	group: ${{ github.workflow }}-${{ github.ref }}
	cancel-in-progress: true

	on:
	# Trigger the workflow on push or pull request,
	# but only for the master branch
	push:
	branches:
	- master
	pull_request:
	branches:
	- master

	jobs:
	flake8:

	runs-on: ubuntu-latest

	steps:
	- uses: actions/checkout@v4
	- name: Set up Python 3.9
	uses: actions/setup-python@v5
	with:
	python-version: 3.9
	- name: Install dependencies
	run: \|
	python -m pip install --upgrade pip
	pip install flake8
	- name: Lint with flake8
	run: \|
	flake8 --builtins=ArgumentError .

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