val map : 'a list -> f:('a -> ('b, 'e) t) -> ('b list, 'e) tval all : ('a, 'error) t list -> ('a list, 'error) tval iter : 'a list -> f:('a -> (unit, 'error) t) -> (unit, 'error) tval concat_map : 'a list -> f:('a -> ('b list, 'error) t) -> ('b list, 'error) tval fold_left : 'a list -> f:('acc -> 'a -> ('acc, 'c) result) -> init:'acc -> ('acc, 'c) result