val validate_list :
([> `Index of int ] as 'a list -> 'b -> 'c option) ->
'a list ->
'b list ->
'c option
val validate_array :
([> `Index of int ] as 'a list -> 'b -> 'c option) ->
'a list ->
'b array ->
'c option
val validate_option : ('a -> 'b -> 'c option) -> 'a -> 'b option -> 'c option