A simple snap-on latch for my printer enclosrue wall cupboard doors. (See the fitting doorknobs here: https://www.thingiverse.com/thing:3586949).

Slides over the base of one doorknob and clicks firmly over the other one, given that the distance of the centers of the doorknobs is 93mm. If you need different distances, just let me know, and I also included the blender file, so changing the distance should be pretty easy.