Flexi Multi-Box bag dispenser conversion

Flexi Multi-Box for Flexi Leash https://www.amazon.de/dp/B0114IG15O has one problem - it's useless as a poop bag dispenser. This door turns it into a proper one. It goes in place of a stock silicone door and puts exactly right amount of tension on the poop bag for it to always be readily available.

Print material: TPU

Print settings: Whatever works. I've printed it in “standing” orientation, with skirt and supports, see screenshot.