没有已知的选择器类的方法＆＃39; getInstance＆＃39;

Question

#import "CacheManager.h"

@implementation CacheManager

//Get an Instance of Cache Manager Class
+(instancetype) getInstance {
    static dispatch_once_t once;
    static CacheManager *sinstance=nil;
    if(sinstance==nil){
        dispatch_once(&once, ^{
            sinstance = [[CacheManager alloc]init];
        });
    }
    return sinstance;
}

#import "Resturant.h"

@implementation Resturant

-(instancetype) initWithDictionary:(NSDictionary*)dictionary {
    self = [super init];
    if (self && dictionary) {
        self.iD=dictionary[KZOMATO_RESTURANT_KEY][KZOMATO_RESURANT_ID];
        self.name=dictionary[KZOMATO_RESTURANT_KEY][KZOMATO_RESTURANT_NAME];
        self.url=dictionary[KZOMATO_RESTURANT_KEY][KZOMATO_RESTURANT_URL];
        self.photoURL=dictionary[KZOMATO_RESTURANT_KEY][KZOMATO_RESTURANT_PHOTO_URL];
        self.rating=dictionary[KZOMATO_RESTURANT_KEY][KZOMATO_RESTURANT_USER_RATING_KEY][KZOMATO_AGGREGATE_RATTING];
        self.adress=dictionary[KZOMATO_RESTURANT_KEY][KZOMATO_LOCATION_KEY][KZOMATO_ADRESS_KEY];
        self.averageCostForTwo=dictionary[KZOMATO_RESTURANT_KEY][KZOMATO_AVERAGE_COST_KEY];
        self.image = nil;
        self.imageLoaded = FALSE;
        [self getImage:^(UIImage *image) {
            self.image=image;
        }];
        return self;
    }

    return nil;
}

//method to get image from Cached Data
-(void) getImage :(void (^)(UIImage * image))callBack {
    // This line of code getInstance is showing error
    [[CacheManager getInstance]imageForURL:self.photoURL withCompletionHandler:^(UIImage *image) {
        self.imageLoaded = TRUE;
        callBack(image);
    }];
}
@end