Redefining instances 

Make sure the attacker cannot redefine class instances by declaring a more specific instances (after all, you have generic ones in DCLabeles (with a type variable a)). 

https://github.com/OctopiChalmers/Multef/blob/11a5a74b207920b7ab9f9bfc6292c24a93f23995/src/Lattice.hs#L1