generalise VariableIndex and FlexiblyIndexed #354

	name: Build and test

	on:
	# Run on pushes to master
	push:
	branches:
	- master
	# And all pull requests
	pull_request:


	jobs:
	build:
	# The type of runner that the job will run on
	runs-on: ubuntu-latest
	strategy:
	matrix:
	python_version: ['3.8', '3.9', '3.10', '3.11']
	# Don't immediately kill all if one Python version fails
	fail-fast: false
	steps:
	- uses: actions/checkout@v2
	- name: Setup python
	uses: actions/setup-python@v2
	with:
	python-version: ${{ matrix.python_version }}
	- name: Install dependencies
	run: \|
	python -m pip install --upgrade pip
	python -m pip install -r requirements.txt
	pip install flake8 pytest
	- name: Lint
	run: \|
	flake8 .
	- name: Install
	run: \|
	python -m pip install .
	- name: Test
	run: \|
	pytest tests

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