Example code from tutorial given by Matt Makai: https://youtu.be/L5YQbNrFfyw
Referenced in his full stack python site: https://www.fullstackpython.com/websockets.html
pip install flask redis flask-socketio gevent gevent-websocket
click==6.7 Flask==1.0.2 Flask-SocketIO==3.0.1 gevent==1.3.5 gevent-websocket==0.10.1 greenlet==0.4.14 itsdangerous==0.24 Jinja2==2.10 MarkupSafe==1.0 python-engineio==2.2.0 python-socketio==2.0.0 redis==2.10.6 six==1.11.0 Werkzeug==0.14.1
sudo yum install redis $ redis-server