App document icon in spotlight on mac

Hello.

I'm adding my mac app contents to spotlight index. I have created a dedicated exported document type which Finder also recognises and shows documents with my extension "artcl" with correct icon I provide with the app. But it does not happen in Spotlight - it shows my documents with default icon.

I create items for Spotligh index as follows:

    let myType = UTType(filenameExtension: "artcl")!
    var searchableItems: [CSSearchableItem] = []
    for itm in items.reversed() {
        let attributeSet = CSSearchableItemAttributeSet(contentType: myType)
        attributeSet.title = item.title
        attributeSet.contentDescription = item.desc
        attributeSet.displayName = item.name
        attributeSet.keywords = [ item.title ]
        attributeSet.comment = item.title + " " + item.desc
        attributeSet.contentType = "com.devaikin.spottest.artcl"

        let id = "artcl." + item.title + "." + item.name
        let indexItem = CSSearchableItem(uniqueIdentifier: id, domainIdentifier: "artcl", attributeSet: attributeSet)
        searchableItems.append(indexItem)

let defaultIndex = CSSearchableIndex(name: "Spottest")
defaultIndex.deleteAllSearchableItems()
defaultIndex.beginBatch()
defaultIndex.indexSearchableItems(searchableItems)
...

Items are added to the spotlight and I can find them, but default icon is displayed while I would expect my exported type icon to be shown like Finder does it.

Am I missing something in attributeSet setup?