Improving Metadata Query with Enum

[Atralupus]

We have a lot of collections and their metadata.
Currently, we can query like this:

query {
    metadata(collectionName: "arena") {
        latestBlockIndex
    }
}

We already defined collection names here, but it's not an enum.
I don't have any ideas to solve this problem, but I want to be able to query like this:

query {
    metadata(collectionName: ARENA) {
        latestBlockIndex
    }
}

https://graphql.org/learn/schema/#enumeration-types