I'm quite new here too, first post for me and it's a reply :-/....anyway welcome aboard. There was a subscription update back in early April for RTSP support. Maybe this will provide the access you need? See this link to The Meraki Community Subscription Update.
RTSP support has now been released for the MV!
You can also use the MV Sense API. This is a link to the start of the functions for Python (scroll through the menu on the left under MV Sense).
You might find it easier to read the generic REST API docs for this functionality, and then go back to the Python SDK: