Bi-fold door lock thingamajig

I live with cats. Crafty ones with nothing but time on their hands as they ponder what I am pondering. One of these crafty cats has taught the others how to open bi-fold doors. Ugh...

So, while this may be yet another take on the bifold door "lock", this one is mine. :)

Two versions. One has a 4mm hole on the "handle" so you can tie a piece of string or ribbon to it. The string is to serve as a visual aid so that guests don't inadvertently pull on a locked door and potentially damage