type nonrec ('a, 'cmp) t = {tree : ('a, 'cmp) t;name : string;}
val is_subset : comparator:('a, 'cmp) Comparator.t -> ('a, 'cmp) t -> of_:('a, 'cmp) t -> unit Or_error.tval equal : comparator:('a, 'cmp) Comparator.t -> ('a, 'cmp) t -> ('a, 'cmp) t -> unit Or_error.t