iOS show alert controller object

I have more page will show the UIAlertController.

So I need write the alert code in a method and class in one page.

I want to use the class and call the method can show the alert on the any Viewcontroller .

How can I write presentviewcontroller in the class.

my header file is below:

 #import <Foundation/Foundation.h>
 #import "VisionAPI.h"

 @interface VisionAPI : NSObject

 +(void) showMessageAlert:(NSString *) title andMessage:(NSString*) msg andDoneMsg:(NSString*) done;

 @end

My implement file is below:

 #import "VisionAPI.h"
 #import <UIKit/UIKit.h>
 @implementation VisionAPI

 +(void) showMessageAlert:(NSString *) title andMessage:(NSString*) msg andDoneMsg:(NSString*) done{

     UIAlertController *showMsgAlertController = [UIAlertController alertControllerWithTitle: title message: msg preferredStyle: UIAlertControllerStyleAlert];
UIAlertAction *showMsgAlertControllerOkAction = [UIAlertAction actionWithTitle:done  style:UIAlertActionStyleDefault
                                                       handler:nil];
       [showMsgAlertController addAction:showMsgAlertControllerOkAction];
dispatch_async(dispatch_get_main_queue(), ^{

       [self presentViewController:showMsgAlertController animated:YES completion:nil];
     });
 }
 @end

But upper code will show the error in this line:

 [self presentViewController:showMsgAlertController animated:YES completion:nil];

How can I presentViewController in the NSObject, or how to fix the problem.