Lru cache refresh question

Hello, I have a question about the Lru Cache:

https://github.com/msiemens/tinydb/blob/master/tinydb/utils.py#L36

Should the `refresh()` method only append a value only if it already existed and was removed? For example, in when `refresh()` is called in `get()`, I think it's possible that a wrong key will still result in that key being added to the lru.
