def Group.sub_add
import bend-lawful-stdlib@0.1.0.0/src/class.bend as Classimport Base
62def Group.sub_add(-A: Data, d: Group<A>, a: A, b: A) -> {a == Group.sub(A, d, Group.add(A, d, a, b), b) : A}:
63 match d:
64 case Group{add, sub, sub_add, add_sub}:
65 sub_add(a, b)