Global Functions Objective C

Global Functions Objective C

I am trying to write a global function however keep getting the error "No
visible interface...." when i try and call it.
Popover.h
#import <Foundation/Foundation.h>
@interface Popover : NSObject{}
- (void)PopoverPlay;
@end
Popover.m
#import "Popover.h"
@implementation Popover
- (void)PopoverPlay{
NSLog(@"I Work");
}
@end
In View.m i am adding the import "Popover.h" but i cant get rid of the
error message when i try and run.
Any ideas Thanks