include sig ... end
type nonrec t = (Base.String.t, Base.String.comparator_witness) Base__Set.tval of_list :
Base.String.t list ->
(Base.String.t, Base.String.comparator_witness) Base.Set.tval empty : (Base.String.t, Base.String.comparator_witness) Base.Set.tval sexp_of_t : (Base.String.t, 'a) Base.Set.t -> Base__.Sexp.tval union_list :
(Base.String.t, Base.String.comparator_witness) Base.Set.t list ->
(Base.String.t, Base.String.comparator_witness) Base.Set.t