Functor Nonnegative.Imperative

module Imperative: 
functor (G : Sig.IM) ->
functor (W : WEIGHT with type label = G.E.label) -> sig .. end
Parameters:
G : Sig.IM
W : WEIGHT with type label = G.E.label

include Sig.IM
exception Negative_cycle of G.E.t list