sig
val apply_on_opted : ('a -> 'b) -> 'a option -> 'b option
val apply_opted : ('a -> 'b) option -> 'a -> 'b option
val cb_on_opted : ('a -> 'b) -> 'a option -> unit
val cb_opted : ('a -> 'b) option -> 'a -> unit
val unopt : ?exc:exn -> ?default:'a -> 'a option -> 'a
val assoc_opt : 'a -> ('a * 'b) list -> 'b option
val string_of_t_opt : ('a -> string) -> 'a option -> string
val t_opt_of_string : (string -> 'a) -> string -> 'a option
val optionnaly_add_to_list : 'a list -> 'a option -> 'a list
end