     
     
     /**
-    For perform in background queue
+    Perform block in background queue and save and wait till done.
     
     :param: block
-    :param: failure
+    :param: error
+    :returns: true if successfully saved.
     */
     public class func saveWithBackgroundBlockAndWait(block: (Void -> Void)?, error: NSErrorPointer) -> Bool {
         if let driver = self.driver {

    }
    
    /**
    For peform in background queue : Manually call timing of save.(Directed to asynchronous processing in block)
    
    :param: block
    :param: failure
    */
    public class func saveWithBackgroundBlock(block: (() -> Void)?, saveSuccess: (() -> Void)?, saveFailure: ((error: NSError?) -> Void)?) {
        if let driver = self.driver {

    }
    
    /**
    Perform in background queue and save (Manually call timing of save.)
    
    :param: block
    :param: saveSuccess
    :param: saveFailure
    */
    public class func saveWithBackgroundBlockWaitSave(block: ((doSave: (() -> Void)) -> Void)?, saveSuccess: (() -> Void)?, saveFailure: ((error: NSError?) -> Void)?) {
        if let driver = self.driver {
