Improve code and typing to pass mypy --no-strict-optional #27

	name: Check links in markdown

	on: push

	jobs:
	test_links_in_readme:
	runs-on: ubuntu-22.04
	steps:
	- uses: actions/checkout@v3
	- name: List files
	run: ls -la
	- uses: docker://pandoc/core:2.9
	with:
	args: >- # allows you to break string into multiple lines
	--standalone
	--from markdown
	--output=readme.html
	README.md
	- name: Run htmltest
	uses: wjdp/htmltest-action@master
	with:
	path: readme.html

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