title: Read data from firebase swift
body: <p>I'm trying to retrieve data from firebase database, but when I run the code it display nothing, though no errors shown</p>
  
  <p>I got this piece of code from Firebase manual, by the way, I'm pretty sure that the path is correct</p>
  
  <pre><code>let ref = FIRDatabase.database().reference()
  
  ref.child("users").child("user").child(username).observeSingleEvent(of: .value, with: { (snapshot) in
          // Get user value
          let value = snapshot.value as? NSDictionary
          let score = value?["score"] as? String ?? ""
          print(score)
  
          // ...
      }) { (error) in
              print(error.localizedDescription)
  }
  </code></pre>
  
  <p>JSON</p>
  
  <pre><code>{
    "users" : {
      "user" : {
        "e1410kokeZS8xv81J1RzhN4V2852" : {
          "email" : "aaaa@gmail.com",
          "score" : 0,
          "username" : "Afnan"
        },
        "jPx8XJ3Q9AazDM7qIOhz02PBfh22" : {
          "email" : "aaaa@ggg.com",
          "score" : 13,
          "username" : "ghhh"
        }
      }
    }
  }
  </code></pre>