|  | // Package cache defines an interface for an LRU cache. | 
|  | package cache | 
|  |  | 
|  | import "context" | 
|  |  | 
|  | // Cache in an interface for an LRU cache. | 
|  | type Cache interface { | 
|  | // Add adds a value to the cache. | 
|  | Add(key string) | 
|  |  | 
|  | // Exists returns true  if the key is found in the cache. | 
|  | Exists(key string) bool | 
|  |  | 
|  | // SetValue sets the value for the given key in the cache. | 
|  | SetValue(ctx context.Context, key string, value string) error | 
|  |  | 
|  | // GetValue returns the value for the corresponding key from the cache. | 
|  | GetValue(ctx context.Context, key string) (string, error) | 
|  | } |