This `.to_i` is here because the first time the method is called, `@health` is probably `nil`. When you compare `current_health` to `nil`, Ruby raises an error.

By calling `nil.to_i` we get `0`, which is good enough.

I do kinda wish this extra `.to_i` call didn’t exist, since it makes you look twice the first time you look at it as you wonder why it exists.