Simple 2 hour process that consists of two rounds. One by co-worker, another by engineering manager. Understand basics of python (they also have PHP, so that too if you want to) and webapps. Understand CRUD of all data structures and you will easily crack it. If you are a backend guy looking for a full stack role, it's a good opportunity so read up on front end interview stuff. If they ask, you should know. If you fail, you can still make it as they are very forgiving people, just ask them to ask more questions. In the end, you should have answered lots of questions so they don't remember where you failed.