Selecting/finding vertices with more than n vertex groups

Hey, I’m working on a slightly convoluted custom rig for a unity game and need to keep my joints per vertex under 4. Which is fine for the most part, but there are some complex areas where more bones compete for an area.
I know I can just use the “limit groups per vert” option, but that tends to be unpredictable and Its kind of a black box as for where the changes occur.

Is there a way to highlight (select) all the verts which have more than n vertex groups assigned to them so I can get a quick overview without making any actual changes.

Perhaps someone can advise me on how one would do this via script?

Thanks a bunch.