func getContext () -> NSManagedObjectContext {
        let appDelegate = UIApplication.shared.delegate as! AppDelegate
        return appDelegate.persistentContainer.viewContext
    }

    func storePersonInfo (identification: Int, surname: String, givenName: String, dateOfBirth: Date) {
        let context = getContext()

        //retrieve the entity that we just created
        let entity =  NSEntityDescription.entity(forEntityName: "Person", in: context)

        let transc = NSManagedObject(entity: entity!, insertInto: context)

        //set the entity values
        transc.setValue(identification, forKey: "identification")
        transc.setValue(surname, forKey: "surname")
        transc.setValue(givenName, forKey: "givenName")
        transc.setValue(dateOfBirth, forKey: "dateOfBirth")

        //save the object
        do {
            try context.save()
            print("saved!")
        } catch let error as NSError  {
            print("Could not save \(error), \(error.userInfo)")
        } catch {

        }
    }

    func getPersonInfo () -> String {
        var info = ""
        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = "dd-MM-yyyy"

        //create a fetch request, telling it about the entity
        let fetchRequest: NSFetchRequest<Person> = Person.fetchRequest()

        do {
            //go get the results
            let searchResults = try getContext().fetch(fetchRequest)

            //I like to check the size of the returned results!
            print ("num of results = \(searchResults.count)")

            //You need to convert to NSManagedObject to use 'for' loops
            for trans in searchResults as [NSManagedObject] {
                let id = String(trans.value(forKey: "identification") as! Int)
                let surname = trans.value(forKey: "surname") as! String
                let givenName = trans.value(forKey: "givenName") as! String
                let strDate = dateFormatter.string(from: trans.value(forKey: "dateOfBirth") as! Date)
                info = info + id + ", " + givenName + " " + surname + ", " + strDate + "\n"
            }
        } catch {
            print("Error with request: \(error)")
        }
        return info;
    }

    func removeRecords () {
        let context = getContext()
        // delete everything in the table Person
        let deleteFetch = NSFetchRequest<NSFetchRequestResult>(entityName: "Person")
        let deleteRequest = NSBatchDeleteRequest(fetchRequest: deleteFetch)

        do {
            try context.execute(deleteRequest)
            try context.save()
        } catch {
            print ("There was an error")
        }
    }

}