fact: Definition make_signature_simple {ns: nat} (ar: list (list (⟦ ns ⟧) × ⟦ ns ⟧)) : signature_simple := ns ,, ar.
imports: UniMath.MoreFoundations.Notations UniMath.Combinatorics.StandardFiniteSets UniMath.Combinatorics.DecSet UniMath.Combinatorics.MoreLists