Using `Any` as type raises an exception:

> 
> Terminating app due to uncaught exception 'RLMException', reason:
>  'Property 'value' is declared as 'Swift.\_NSContiguousString', which is
>  not a supported RLMObject property type. All properties must be
>  primitives, NSString, NSDate, NSData, NSNumber, RLMArray,
>  RLMLinkingObjects, or subclasses of RLMObject. See
>  <https://realm.io/docs/objc/latest/api/Classes/RLMObject.html> for more
>  information.'
> 
> 
>