ちょっと微妙なんだけど、これはどうかしら?

```ruby
before_save :amazon_title
before_save :amazon_image_url

private
def amazon
   @amazon ||= Amazon.new(isbn, isbn_type)
end

def amazon_title
  self.title = amazon.book_title
end

def amazon_image_url
  self.image_url = amazon.book_image_url
end
```