[API] Audiobooks API returns 404 not found for shows

[Keiwen]

Hi there,

I'm starting development on Spotify API, and found a potential bug.

On search API, I query for Harry Potter audiobooks (GET /v1/search?q=harry+potter&type=audiobook) that returns some results :

- Harry Potter and the Sorcerer's Stone (ID 2IEBhnu61ieYGFRPEJIO40)

- Harry Potter and the Chamber of Secrets (ID 7F4mIpx6PDOso7MkSErKLK)

- Harry Potter and the Prisoner of Azkaban (ID 5ISJuqOKhpFJyU9qlPK2rF)

- ...

At this point, I tried to call audiobook method (/v1/audiobooks/{id}) with previous ID retrieved, for example GET /v1/audiobooks/7F4mIpx6PDOso7MkSErKLK

On all IDs I tried, I always get a similar 404 error, for example : 

Non existing id: 'spotify:show:7F4mIpx6PDOso7MkSErKLK'

Regarding that error message, it seems that it is looking a show type while I'm asking for a audiobook type. I guess this is the root cause of why I cannot found an audiobooks with the ID retrieved in search method.

Could you please look at it?

Thanks