The idea is to take service-oriented approach. You have Angular frontend application to serve the pages and a backend application (using one of the above frameworks you choose) to serve the Python code. When required to execute the Python code, some action on your Angular application would call an API served by your backend. This API will point to some form of method where you can run your Python code as necessary, and serve back either the visualization itself or any data as a blob/json response that Angular can read/consume.