title: Firebase,Swift : Not able to retrieve Data
body: <p>I'm trying to do a simple task, to get a value from Firebase. 
  I added the image below with the relevant screens. At least one of the print commands should print a message to the console, but it's not working. I've been trying to fix it for 1,5 days now and I still have no idea why it is not working.</p>
  
  <p>Code:</p>
  
  <pre><code>import UIKit
  import Firebase
  
  class MainVC: UIViewController {
  
      override func viewDidLoad() {
          super.viewDidLoad()
  
          let ref = FIRDatabase.database().reference()
  
          ref.child("zonneschijn").observeSingleEventOfType(.Value, withBlock: { snapshot in
              if snapshot.value is NSNull {
                  print("Does not exist currently")
              } else {
                  print("Exists currently")
              }
  
          })
      }
  }
  </code></pre>
  
  <p>I've also tried to use viewDidAppear, also with no succes.</p>
  
  <p><a href="https://i.stack.imgur.com/1naNm.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/1naNm.png" alt="Image with the relevant screens"></a></p>