You have the right idea here with using a constant, but you can't mix the two. Instead, I'd just use `@yahoo_fin_api`. It's okay that you're not using a constant in this case, but if you decide that you want to, typically we put them immediately after the class definition, so it'd look something like this:

```ruby
class Stock
  YAHOO_FIN_API = YahooFinanceApi.new

...

end
```