The method name here is a tad confusing. It sounds interrogative, like "is it lost?" This might trip up experienced Ruby devs because they'd be used to seeing a method like this:

```ruby
def is_lost?
  book.status == 'Lost'
end
```

You can clarify things by making method names imperative, like so:

```ruby
def record_as_lost
  book.status = 'Lost'
end
```