Derive Macro ListHashes 

#[derive(ListHashes)]
{
    // Attributes available to this derive:
    #[topology]
}

use object_rainbow::ListHashes;

#[derive(ListHashes)]
struct Three<A, B, C> {
    a: A,
    b: B,
    c: C,
}

object_rainbow::assert_impl!(
    impl<A, B, C> ListHashes for Three<A, B, C>
    where
        A: ListHashes,
        B: ListHashes,
        C: ListHashes,
    {}
);