let mem: elt => t => bool;
let remove: elt => t => t;
let disjoint: t => t => bool;
let compare: t => t => int;
let equal: t => t => bool;
let subset: t => t => bool;
let iter: (elt => unit) => t => unit;
let fold: (elt => 'a => 'a) => t => 'a => 'a;
let for_all: (elt => bool) => t => bool;
let exists: (elt => bool) => t => bool;
let filter: (elt => bool) => t => t;
let partition: (elt => bool) => t => (t, t);
let elements: t => list(elt);
let min_elt_opt: t => option(elt);
let max_elt_opt: t => option(elt);
let choose_opt: t => option(elt);
let find_opt: elt => t => option(elt);
let of_list: list(elt) => t;
let of_increasing_iterator_unchecked: (unit => elt) => int => t;
let of_sorted_array_unchecked: array(elt) => t;
let find_first_opt: (elt => bool) => t => option(elt);