Module Equality

module Equality: sig .. end

module type Element = sig .. end

module Make: 
functor (Elt : Element) -> 
functor (Set : Hptset.S  with type elt = Elt.t) -> 
functor (Functor_info : Datatype.Functor_info) -> Equality_sig.S_with_collections  with type elt = Elt.t