fixed import error #18

	name: Build Status

	on: [push]

	jobs:
	build:

	runs-on: ubuntu-latest

	steps:
	- uses: actions/checkout@v1
	- name: Set up Python 3.7
	uses: actions/setup-python@v1
	with:
	python-version: 3.7
	- name: Install dependencies
	run: \|
	python -m pip install --upgrade pip
	pip install networkx
	pip install black codecov flake8 mypy pytest pytest-cov
	- name: Lint with flake8
	run: \|
	# stop the build if there are Python syntax errors or undefined names
	flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
	# exit-zero treats all errors as warnings.
	flake8 . --count --exit-zero --max-complexity=10 --max-line-length=160 --statistics
	- name: Install and run Black
	run: black --check .
	- name: Typechecking with mypy
	run: mypy . --ignore-missing-imports
	- name: Test with pytest
	run: \|
	pytest --cov=./ --cov-report=xml
	codecov

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