I have been testing this magnetic cover (6x3mm neodynium magnets, not all slots are needed) with a trash bag on the end for the last couple of months and it just works amazing. I have over 3000 poops in there and never had a single problem.
It is a quick and easy print and it is realy amazing with any kind of trash bag!
printed mine in XZN rainbow glow in the dark ;) if you where wondering