sig
class virtual ['a, 'b] start :
object ('c)
method private virtual guard : ('c, 'a, 'b, unit) Cf_state_gadget.guard
method start : ('d, 'a, 'b, unit) Cf_state_gadget.t
end
class virtual ['a, 'b] next :
object ('c)
method private virtual guard : ('c, 'a, 'b, unit) Cf_state_gadget.guard
method next : ('c, 'a, 'b, 'd) Cf_state_gadget.t
end
end