fact: Definition tuto_sum_enum (T1 T2 : finType) : seq (T1 + T2) := map (@inl _ _) (Finite.enum T1) ++ map (@inr _ _) (Finite.enum T2).
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq path) mathcomp(choice fintype tuple finset)