         }
     }
     
-    private func file(atIndex index:Int) -> String {
+    private func file(at index:Int) -> String {
         return self.directory.stringByAppendingPathComponent(path: "\(self.fileName)\(index <= 0 ? "" : String(index)).\(self.ext)")
     }
     

        }
    }
    
    private func moveFileToNextIndex(fromIndex index:Int) {
        let potentialExistingRolledFile = self.file(atIndex: index)
        if self.fileManager.fileExists(atPath: potentialExistingRolledFile) {
            let newPath = self.file(atIndex: index + 1)
            self.moveFile(fromPath: potentialExistingRolledFile, toPath: newPath)
        }
    }

        self.deleteLastFileIfNeeded()
        
        for index in stride(from: Int(lastIndex), to: -1, by: -1) {
            self.moveFileToNextIndex(from: index)
        }
    }
    
    private func deleteLastFileIfNeeded() {
        let lastFile = self.file(at:Int(self.lastIndex))
        if self.fileManager.fileExists(atPath: lastFile) {
            do {
                try self.fileManager.removeItem(atPath: lastFile)
