Modeling a tree-structure taxonomy in Sanity for Norwegian regions

const viken = {
  name: 'vikenSelector',
  title: 'Viken',
  type: 'object',
  options: {
    collapsible: true,
    collapsed: true,
  },
  fields: [
    {
      title: 'Hvor i Viken?',
      name: 'vikenOverview',
      type: 'array',
      options: {
        list: [
          { title: "Hele viken", value: "viken" }, 
          { title: "Fredrikstad", value: "fredrikstad" }, 
          { title: "Moss", value: "moss" } 
        ]
      },
      of: [
        {
          type: 'string'
        }
      ]
    }
  ]
}

const fylkeTest = {
  name: 'where',
  title: 'Hvor?',
  type: 'object',
  fields: [
    viken
  ]
}