Where is it? Find the tutorial here.
What is it? Learn how to use web sockets to build a simple client server chat application in python. The tutorial also looks at how to use Tornado, a python networking library to implement long lived connections with thousands of users at once making it a great tool to use when scaling your app.
What you need to follow? Basic python experience is enough as the tutorial is an introductory guide to network programming only implementing the basic features for any chat app. You will also need the Python program installed on your computer and an IDE of your choosing.