Ordering a list by frequency in Swift

I have a list of items that I want order by frequency, so that

var entries = ["one", "three", "one", "two", "one", "two"]

becomes

    ["one", "two", "three"]

I used the Swift dictionary grouping to do it:

extension Sequence where Element : Hashable {
    func byFrequency() -> [Element] {
        Dictionary(grouping: self, by: {$0}).sorted{ (a, b) in
            a.value.count > b.value.count
        }.map { $0.key}
    }
}

entries.byFrequency()

gives

    ["one", "two", "three"]