Swift UITableView AccessoryType (checkmark)

I am using tableview accessory.Type (checkmark) in Tableview(didSelectRowAt:). When user click the row without checkmark, the checkmark will appear. When click the row with checkmark, the checkmark will disappear. Below is the code:

if cell?.accessoryType == .checkmark {
    cell?.accessoryType = .none
} else {
    cell?.accessoryType = .checkmark
}

The above code is working as expected. When change to the following, it doesn’t work. Any idea?

if cell?.accessoryType == .none {
   cell?.accessoryType = .checkmark
} else {
    cell?.accessoryType = .none
}