val return : 'a -> ('b, 'a) tval return_left : 'a -> ('a, 'b) tval of_option : left:'a -> 'b option -> ('a, 'b) tval of_result : ('a, 'b) Result.result -> ('b, 'a) tUtils.EitherMonadval return : 'a -> ('b, 'a) tval return_left : 'a -> ('a, 'b) tval of_option : left:'a -> 'b option -> ('a, 'b) tval of_result : ('a, 'b) Result.result -> ('b, 'a) t