- print(book.extra_info.get('cover_by'))
- print(book.extra_info.get('cover_source'))
- print(book.extra_info.get('cover_url'))
+ extra_info = book.get_extra_info_json()
+ print(extra_info.get('cover_by'))
+ print(extra_info.get('cover_source'))
+ print(extra_info.get('cover_url'))