Representing Coordinates from Firebase as Annotations Swift - swift

Question

I am having trouble putting annotations on my map from longitudinal and latitudinal degrees I uploaded to firebase. I want to add an annotation for all of my users but cannot get xcode to recognize my userLatitude and userLongitude variables in another function.
Anything will help!
func retrieveUsers(){
let ref = Database.database().reference()
ref.child("users").queryOrderedByKey().observeSingleEvent(of: .value, with: { snapshot in
let users = snapshot.value as! [String: AnyObject]
self.user.removeAll()
for (_,value) in users {
if let uid = value["uid"] as? String {
if uid != Auth.auth().currentUser!.uid {
let userToShow = User()
if let fullName = value["full name"] as? String,
let imagePath = value["urlToImage"] as? String,
//String(format: "%f", self.currentUserLocation?.longitude ?? 0),
let userLongitude = value["long"] as? CLLocationDegrees,
let userLatitude = value["lat"] as? CLLocationDegrees
//why isnt it recognizing the users degrees
{
userToShow.fullName = value["full name"] as? String
userToShow.imagePath = value["urlToImage"] as? String
userToShow.userID = value["uid"] as? String
userToShow.userLongitude = value["long"] as? CLLocationDegrees
userToShow.userLatitude = value["lat"] as? CLLocationDegrees
self.user.append(userToShow)
}
}
}
}
DispatchQueue.main.async {
self.map.reloadInputViews()
//not sure if this is right
}
})
}
func mapView(_ mapView: MKMapView, didAdd views: [MKAnnotationView]) {
let otherUserLocation: CLLocationCoordinate2D = CLLocationCoordinate2DMake(userLatitude, userLongitude)
let userAnnotation = MKPointAnnotation()
userAnnotation.coordinate = otherUserLocation
userAnnotation.title = "fullName"
}

Answer 1

And if you change as? CLLocationDegrees by as? String and manage the cast in CLLocationDegrees afterwards?
Because I think, in Firebase, data is stored as String and not as Double (that is the type of data a CLLocationDegrees type is referring to).