I have followed loads of questions here but nothing seems to work.
I am using Swift3 in a Playground. Running on El Capitan and Xcode 8.1.
You are using the wrong API, you need to load Data rather than something in the file system.
if let url = Bundle.main.url(forResource: "levelList", withExtension: "plist"),
let plistData = try? Data(contentsOf: url ) {
let mydata = try! PropertyListSerialization.propertyList(from: plistData, options: [], format: nil) as! [String:Any]
}