Can I add views to the same hierarchy in XCode while splitting them into functions? – Ios swift

I am new to XCode, and I am trying to render a different subview based on a condition. To achieve this, I created two separate files that return a UIView:

This is the occupied space file:

import UIKit

func createOccupiedSpaceView(color: UIColor, playerName: String) -> UIView {
    let occupiedView = UIView()
    occupiedView.backgroundColor = color
    
    return occupiedView
}

and this is the unoccupied space file:

func createUnoccupiedView(color: UIColor) -> UIView {
    let unoccupiedView = UIView()
    unoccupiedView.backgroundColor = color
    
    let addLabel = UILabel()
    addLabel.text = "ADD NEW PLAYER"
    
    addLabel.anchor(top: unoccupiedView.topAnchor, leading: unoccupiedView.leadingAnchor, bottom: unoccupiedView.bottomAnchor, trailing: unoccupiedView.trailingAnchor, size: CGSize(width: 20, height: 20))
    
    [addLabel].forEach({unoccupiedView.addSubview($0)})
    
    return unoccupiedView
}

I have also created this extension to make my constraints easier

extension UIView {
    func anchor(top: NSLayoutYAxisAnchor?, leading: NSLayoutXAxisAnchor?, bottom: NSLayoutYAxisAnchor?, trailing: NSLayoutXAxisAnchor?, padding: UIEdgeInsets = .zero, size: CGSize = .zero) {
        
        translatesAutoresizingMaskIntoConstraints = false
        
        if let top = top {
            topAnchor.constraint(equalTo: top, constant: padding.top).isActive = true
        }
        
        if let leading = leading {
            leadingAnchor.constraint(equalTo: leading, constant: padding.left).isActive = true
        }
        
        if let bottom = bottom {
            bottomAnchor.constraint(equalTo: bottom, constant: -padding.bottom).isActive = true
        }
        
        if let trailing = trailing {
            trailingAnchor.constraint(equalTo: trailing, constant: -padding.right).isActive = true
        }
        
        if size.width != 0 {
            widthAnchor.constraint(equalToConstant: size.width).isActive = true
        }
        
        if size.height != 0 {
            heightAnchor.constraint(equalToConstant: size.height).isActive = true
        }

    }

Here is the view controller that runs the code:

import UIKit

class LobbyVC: UIViewController {
    private let game: Game
    
    init?(coder: NSCoder, game: Game) {
        self.game = game

        super.init(coder: coder)
    }
    
    required init?(coder: NSCoder) {
        fatalError("Use `init(coder:game:)` to initialize an `LobbyVC` instance.")
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // Get appropriate player space views
        let VALID_PLAYER_POSITIONS = [1, 2, 3, 4]
        var playerDictionary = [Int: UIView]()

        for position in VALID_PLAYER_POSITIONS {
            playerDictionary[position] = getCorrectView(position: position)
        }

    }
    
    func getCorrectView(position: Int) -> UIView{
        if let player = self.game.players.filter({$0.position == position}).first {
            return createOccupiedSpaceView(color: .green, playerName: player.name)
        } else {
            return createUnoccupiedView(color: .green)
        }
    }
}

I believe that adding constraints to my unoccupied space is creating issues for me, but I am unsure how to split up my views and make my code cleaner while keeping my views in the same hierarchy. Each time that I try to run my code, I get this error:

Thread 1: "Unable to activate constraint with anchors <NSLayoutYAxisAnchor:0x600001fbc500 "UILabel:0x12fd12fa0.top"> and <NSLayoutYAxisAnchor:0x600001fbc040 "UIView:0x12fd07f70.top"> because they have no common ancestor.  Does the constraint or its anchors reference items in different view hierarchies?  That's illegal." 

Any help on solving would be appreciated!