How to model a Map[str, interface]

I want to model some data structured like map[str, my_interface]. My first attempt (based on this GraphQL suggestion) was to introduce a new KeyValue type with the key: String and value: MyInterface and then use a list of those, for example:

interface PartitionKey {
  id: Int!

type DatePartitionKey implements PartitionKey {
  key: DateTime!

type StringToPartitionKey {
  key: String!
  value: PartitionKey!

type Partition {
  keys: [StringToPartitionKey!]!

However, when trying to use the query builder, it generates a mutation like:

addPartition(input: {keys: {key: "date"}})

Which notably:

  • only allows for entering 1 entry for keys (instead of a list)
  • does not allow entering the value (in this case, I want to generate a new DatePartitionKey)
  • does run and creates faulty data (the .keys field is not a StringToPartitionKey value w/ not-null fields, but a random object with just a key field)

Is using a [KeyValue!]! a reasonable approach here and if so, how should this insert mutation be structured? Thanks for any help!