fix lint error #264

	name: lint

	on: [push, pull_request]

	jobs:
	lint:
	runs-on: ubuntu-20.04
	steps:
	- name: Checkout dnfile
	uses: actions/checkout@v2
	- name: Set up Python 3.8
	uses: actions/setup-python@v2
	with:
	python-version: "3.8"
	- name: Install tox
	run: pip install tox
	- name: Lint with isort and pycodestyle
	run: tox -e lint
	- name: Check types with mypy
	run: tox -e type

	test:
	runs-on: ubuntu-20.04
	steps:
	- name: Checkout dnfile
	uses: actions/checkout@v2
	with:
	submodules: true
	- name: Set up Python 3.8
	uses: actions/setup-python@v2
	with:
	python-version: "3.8"
	- name: Install tox
	run: pip install tox
	- name: Run tests
	run: tox -e py38

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