test_stream: add missing return type #125

	name: lint

	on:
	push:
	paths:
	- 'streamable/**'
	- 'tests/**'

	jobs:
	lint:
	runs-on: ubuntu-latest

	steps:
	- uses: actions/checkout@v1
	- name: Set up Python 3.8
	uses: actions/setup-python@v1
	with:
	python-version: 3.8

	- name: checks
	run: \|
	python -m pip install -r .github/workflows/requirements.txt
	python -m autoflake --in-place --remove-all-unused-imports --remove-unused-variables --ignore-init-module --check -r streamable tests
	python -m black --check .

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