val map : f:('a -> 'b) -> 'a option -> 'b optionval apply : f:('a -> 'b option) -> 'a option -> 'b optionval iter : f:('a -> unit) -> 'a option -> unitval unopt : default:'a -> 'a option -> 'aval unopt_map : f:('a -> 'b) -> default:'b -> 'a option -> 'bval first_some : 'a option -> 'a option -> 'a optionval try_with : (unit -> 'a) -> 'a optionval some : 'a -> 'a option