Setting UILabels to Firestore data

Hi,
I would like to be able to take two fields of a firestorm document and then set two UILabels to those fields. Here is my code:

import UIKit
import SafariServices
import WebKit
import Firebase

class TheRiddle: UIViewController {
    
    @IBOutlet weak var leading_TheRiddle: NSLayoutConstraint!
    @IBOutlet weak var trailing_TheRiddle: NSLayoutConstraint!
    
    @IBOutlet weak var CurrentRiddle: UILabel!
    @IBOutlet weak var PreviousRiddle: UILabel!
    
    var menuOut = false
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        let db = Firestore.firestore()
        
        db.collection("TheRiddle").document("Riddles").getDocument { (document, error) in
            
            //check for error
            if error == nil {
                //check if document exists
                if document != nil {
                }else {
                    if let currentRiddle = document!.get("CurrentRiddle") as? String {
                        self.CurrentRiddle.text = "This Weeks Riddle: " + currentRiddle
                    }
                    if let previousRiddle = document!.get("CurrentRiddle") as? String {
                        self.CurrentRiddle.text = "Previous Riddle: " + previousRiddle
                    }
                }
            }
            
        }
        
        
    }
    
    
    @IBAction func RiddleAnswerForm(_ sender: Any) {
        let vc = SFSafariViewController(url: URL(string: "https://forms.office.com/Pages/ResponsePage.aspx?id=ytAqTDte6UK-KD5v_kOm4Y843IzqmYtFlDtLrfRYsi1UMFpUMk1GN01GS05BVFlJUElONk4yR1hKUCQlQCN0PWcu")!)
        
        present(vc, animated: true)
    }
    
    @IBAction func menuTappedTheRiddle(_ sender: Any) {
        
        if menuOut == false {
            leading_TheRiddle.constant = 150
            trailing_TheRiddle.constant = -150
            menuOut = true
        }
        else {
            leading_TheRiddle.constant = 0
            trailing_TheRiddle.constant = 0
            menuOut = false
        }
        UIView.animate(withDuration: 0.2, delay: 0.0, options: .curveEaseIn, animations: {
            self.view.layoutIfNeeded()
        }) { (animationComplete) in
            print("The animation is complete")
        }
}
}

Update: my code was under the wrong condition