how can I use enum for collection of types

[Miri]

I have a field in an object which I would like to be of the type which is one 
of a pre-existing enum
    
    
    type foo = enum int, bool
    
    type bar = object
        a: seq or foo
    
    
    Run

however this results in a type mismatch. How can I extract the data from the 
enum like i'd like?