Memory cache crash

[mojidabckuu]

- (id)objectForKey:(NSString *)key expires:(NSDate *)expires withContent:(id(^)())content
{
    CKCacheContent *cacheContent = [self objectInMemoryForKey:key];

    if (cacheContent == nil && content != nil) {
        id object = content();
        if (object != nil) {
            cacheContent = [CKCacheContent cacheContentWithObject:object expires:expires];
            [_internalCache setObject:cacheContent forKey:key];
        }
    }

    return cacheContent.object;
}

- (id)objectInMemoryForKey:(NSString *)key
{
    CKCacheContent *cacheContent = [_internalCache objectForKey:key];

    if (cacheContent.expires.timeIntervalSinceNow < 0.0) {
        [_internalCache removeObjectForKey:key];
        cacheContent = nil;
    }

    return cacheContent.object;
}

When I try to extract value from the cache it gives crash because inside - (id)objectInMemoryForKey:(NSString *)key you return id object and then in - (id)objectForKey:(NSString *)key expires:(NSDate *)expires withContent:(id(^)())content use it like CKCacheContent.