Update visualizer.py. Fix import when no GUI #1087

	name: Style check

	on:
	workflow_dispatch:
	push:
	branches: [main, dev]
	pull_request:
	types: [opened, reopened, synchronize]

	jobs:
	style-check:
	runs-on: ubuntu-20.04
	steps:
	- name: Checkout source code
	uses: actions/checkout@v3
	with:
	submodules: true
	- name: Set up Python version
	uses: actions/setup-python@v4
	with:
	python-version: 3.6
	- name: Install dependencies
	run: \|
	python -m pip install -U clang-format==10.0.1.1 yapf==0.30.0 nbformat pydocstyle==6.0.0
	- name: Run style check
	run: \|
	python ci/check_style.py --verbose
	- name: Run docstring style check
	run: \|
	pydocstyle --convention=google --add-ignore=D1,D205,D415,D212 .

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