val to_string : t -> stringval of_string : string -> t optionval to_assoc_list : t -> (string * string) listval of_assoc_list : (string * string) list -> (t, string) Stdlib.resultConproto.Stateval to_string : t -> stringval of_string : string -> t optionval to_assoc_list : t -> (string * string) listval of_assoc_list : (string * string) list -> (t, string) Stdlib.result