Refactor `get_BZ` and implement `BZ` class #59

	name: Continuous integration

	on: [push, pull_request]

	jobs:
	precommit:
	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: Install python dependencies
	run: \|
	pip install -r optional-requirements.txt
	pip install -e .[dev,bz]
	pip freeze

	- name: Run pre-commit
	run:
	pre-commit run --all-files \|\| ( git status --short ; git diff ; exit 1 )

	tests:
	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: Install python dependencies
	run: \|
	pip install -e .[dev,bz]
	pip freeze

	- name: Run the tests
	run: pytest

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