@interface EmptyClass : NSObject
-(void)aMessage:(id)arg;
@end

@interface EmptyClass : NSObject {}
-(void)aMessage:(id)arg;
@end

@interface NSObject (ObjectAdditions)
-(void)aMessage:(id)arg;
@end

@protocol TestProtocol
-(void)aMessage:(id)arg;
@end

@interface TestClass : NSObject <TestProtocol> {
}
-(void)aMessage:(id)arg;
@end