     }
     
     public func fetchImage(withURL url: URL?, failure: @escaping (Error) -> Void, success: @escaping (ImageDownload) -> Void) {
-        fetchImage(withURL: url, priority: 0.5, failure: failure, success: success)
+        fetchImage(withURL: url, priority: URLSessionTask.defaultPriority, failure: failure, success: success)
     }
     
     public func cancelFetch(withURL url: URL?) {

        }
    }
    
    public func permanentlyCache(url: URL, groupKey: String, priority: Float = 0, failure: @escaping (Error) -> Void, success: @escaping () -> Void) {
        let key = self.cacheKeyForURL(url)
        let variant = self.variantForURL(url)
        let identifier = self.identifierForKey(key, variant: variant)

    }
    
    public func fetchData(withURL url: URL?, failure: @escaping (Error) -> Void, success: @escaping (Data, URLResponse) -> Void) {
        fetchData(withURL: url, priority: URLSessionTask.defaultPriority, failure: failure, success: success)
    }
    
    
