         
         // skip download if file is already existed
         if (fileManager.fileExistsAtPath(file!) && !isOverwrite) {
-            cb("'The `\(file!)` is already existed.'")
+            cb("{ message: 'The file is already existed.', file: '\(file!)' }")
             return
         }
         

            } catch let error as NSError {
                print(error.localizedDescription)
            }
            cb("'`\(file!)` had been downloaded sucessful.'")
        })
        
        downloadTask.resume()

        } catch let error as NSError {
            print(error.localizedDescription)
        }
        cb("{ message: 'File had been cleared.', file: '\(file!)' }")
    }
    
    /**
