Attempted. Yes
Succeeded. Not at all!
In fact my attempt at a mint chocolate stout was so bad, that it is the only beer I have ever made that I dumped the entire batch down the drain. I'm still not positive what went wrong. We used Dutched Cocoa powder. But I don't think it ever fully disolved, that or the yeast had some odd reaction to it as you could kind of feel the powder in the beer. like when you make hot chocolate but didnt mix it well enough. Also, I think we used too much dried mint as the flavor was overpowering. The beer also had a sour note to it, both in taste and in smell, no idea what caused that. but the whole beer was just an abortion. I have not since tried to make another one and Im not sure I'd want to try again either.