Could not cast value of type '__nscfnumber' (0x1b4520df0) to 'nsstring'

let uid = FIRAuth.auth()?.currentUser?.uid
                let ref = FIRDatabase.database().reference().child("users").child((uid)!)
                ref.observeSingleEvent(of: .value, with: { snapshot in
                    
                    if let dictionary = snapshot.value as? [String: AnyObject] {
                        let htest = dictionary["h"] as! String  //Thread1: signal SIGABRT
                        var inthtest = Int(htest)
                        if (inthtest==0){
                            self.checkPointsk()
                            print("scanning1")