add source code for figure4 #673

	name: Mypy
	on: [push]

	jobs:
	Static-Type-Checking:
	runs-on: ubuntu-latest
	strategy:
	max-parallel: 5

	steps:
	- uses: actions/checkout@v3
	- name: Set up Python 3.11
	uses: actions/setup-python@v4
	with:
	python-version: 3.11.2
	- name: Install dependencies
	run: \|
	pip install --upgrade pip
	pip install -r requirements.txt
	- name: Type-checking package with mypy
	run: \|
	# Manually install mypy in the standard way.
	pip --quiet install -U mypy
	# Log this mypy version for debuggability.
	mypy --version
	# Run this mypy instance against our main package.

Provide feedback