Fix(UT): fix type checker error raised by pyright #241

	name: Python unit-tests

	on:
	- push
	- pull_request

	jobs:
	build:
	runs-on: ubuntu-latest
	strategy:
	matrix:
	python-version: ["3.7", "3.8", "3.9", "3.10"]

	steps:
	- uses: actions/checkout@master
	- name: Set up Python ${{ matrix.python-version }}
	uses: actions/setup-python@master
	with:
	python-version: ${{ matrix.python-version }}
	- name: Install dependencies
	run: \|
	pip install -e .[test]
	pip install mock coverage pytest
	- name: Test
	run: \|
	cd tests
	export SKIP_UT_WITH_DFLOW=0
	export DFLOW_DEBUG=1
	coverage run -m unittest -v -f
	coverage report
	- uses: codecov/codecov-action@v3

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