Just for alternatives: For real-time part you can choose Tornado which has async I/O "out of box". It is very similar to Flask.
Another option would be Twisted. It is "Event-driven networking engine written in Python". Well-documented and widely used.
And Django has now async support; Django Async.
Also here is an example you'd like to look at : Build a live dashboard with Python. I'm not using Pusher or any of their services but the articles seems familiar what you're looking for.
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