From mathcomp.ssreflect
From mathcomp
From fcsl
From DiSeL
From DiSeL
From DiSeL
From DiSeL
From DiSeL
From DiSeL
Export CalculatorProtocol.
Section CalculatorApp.
Definition l1 := 1.
Definition l2 := 2.

Lemma lab_dis : l2 != l1. Proof. by []. Qed.
Definition f args :=
match args with
| x::y::_ => Some (x + y)
| _ => None
end.