The use of `interface`s and `union type`s is at the moment not allowed in Graph.cool. If I have, for example,

type Dress

,

type Shoes

,

type Suit

,

type TShirt

, how can I put them into the list of field

products

in the

type Cart

to reference all products added to the shopping cart? With `union type`s or `interface`s I can unite all my product types under the

type Product

and then put them all to the

products: [Product!]!

field of the

type Cart

. What is the best or recommended practice to do it without `interface`s and `union type`s?