         }
         else {
             writeToFileURL = nil
+            fatalError("FileDestinations must be initialized with a URL or a String")
         }
 
         super.init(owner: owner, identifier: identifier)

        self.shouldAppend = shouldAppend
        self.appendMarker = appendMarker

        if writeToFile is NSString {
            writeToFileURL = URL(fileURLWithPath: writeToFile as! String)
        }
        else if writeToFile is URL {

    @discardableResult open func rotateFile(to archiveToFile: Any) -> Bool {
        var archiveToFileURL: URL? = nil

        if archiveToFile is String {
            archiveToFileURL = URL(fileURLWithPath: archiveToFile as! String)
        }
        else if archiveToFile is URL {
