resources/codegen-resources/customization.config

{
    "verifiedSimpleMethods" : [
        "listDevelopmentSchemaArns",
        "listDirectories",
        "listManagedSchemaArns",
        "listPublishedSchemaArns"
    ],
    "shapeModifiers": {
        "TypedAttributeValue": {
            "union": true
        }
    }
}