This is the rangefinder section. Leica has no 25mm 1.4 rangefinder lens. The topic is also about 28mm 1.4 summilux, not 25mm.
Yours is the Panasonic Leica lens which cannot be fitted in any rangefinder camera nor is there any adapter that i know of.
Anyway, I've used it before (loaned from a friend) and it's an excellent lens which produces some gorgeous images, at least on the M240. I'm hoping to save enough to purchase it in the near future.