Define a couple of declarations as opaque #58

	name: CI

	on: [ push, pull_request ]

	jobs:
	CI:
	name: "Linux x64 (Ubuntu 22.04) - Python ${{ matrix.python-version }}"
	runs-on: ubuntu-22.04
	strategy:
	fail-fast: false
	matrix:
	# Only test supported Python versions:
	# https://endoflife.date/python
	python-version: ["3.8", "3.9", "3.10", "3.11", "3.12", "pypy3.9"]

	steps:
	- name: Checkout code
	uses: actions/checkout@v4

	- name: Set up Python ${{ matrix.python-version }}
	uses: actions/setup-python@v5
	with:
	python-version: ${{ matrix.python-version }}

	- name: Install libvips
	run: sudo apt-get install --no-install-recommends libvips

	- name: Lint with flake8
	run: \|
	pip install flake8
	flake8 .

	- name: Install tox and any other packages
	run: pip install tox

	- name: Run tox
	# Run tox using the version of Python in `PATH`
	run: tox -e py

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