is List<CreamAsset>() legal?

[Marshall-Hu]

Expected behavior

save multi images in List with CreamAsset code could be like: let images = List<CreamAsset>()

        if let images = try? self.imagesRelay.value(){
            var cout = 0
            for image in images {

                if let imageData = image.jpegData(compressionQuality: 1.0) {
                    tree.images.append(CreamAsset.create(object: tree, propName: TreeCard.AVATAR_KEY + cout.description, data: imageData)!)
                }
                cout += 1
            }

            print("NEW tree.images :\(tree.images)")
        }

        try! realm.write {
            realm.add(tree)
        }

Actual behavior(optional)

it seems realm.reslut.images.cout = 0

can someone success add List< CreamAsset > to realmDB? plz point where errors are in my demo code