//  Copyright © 2017 Stefan van den Oord. All rights reserved.

import UIKit
import NetUtils

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        print("\(Interface.allInterfaces())")
    }

}


//  Copyright © 2017 Stefan van den Oord. All rights reserved.

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
    }

}


--- 
+++ 
@@ -1,11 +1,13 @@
 //  Copyright © 2017 Stefan van den Oord. All rights reserved.
 
 import UIKit
+import NetUtils
 
 class ViewController: UIViewController {
 
     override func viewDidLoad() {
         super.viewDidLoad()
+        print("\(Interface.allInterfaces())")
     }
 
 }
Add call to NetUtils to make sure it compiles correctly
