Just find yourself a long running query or create a view that cross joins a quadrillion records (make sure you have the ability to kill this session). Then import oracledb in a notebook, connect to that server, and query that long running query. Proceed to hit cancel in the notebook cell or interrupt in the notebook at the top right. The session doesn't close, you'd need to connection.close(force=True) or pool.close(force=True).
What i'm looking for is a way to catch the 'cancel' button in a cell or the 'interrupt' button in a notebook so I can capture this in a try: except: block and issue the close() command.