Mirror already painted weights

So I made an oopsie (I tend to do that alot I’ve noticed). I thought I had the mirror weight paints on, but I didn’t. And I weighted most of the leg on a model. It’s not too big a deal to redo it, though it’d be annoying. So I’m wondering if it’s possible to mirror already painted weights onto the opposite bone. Or if there’s a script somewhere that’ll let me do that. Google didn’t help any.

Nevermind. Figured it out on my own lol.