>>> Book = namedtuple('Book', ['id', 'title', 'authors'])
>>> Book.__doc__ = 'Hardcover book in active collection'
- >>> Book.id = '13-digit ISBN'
- >>> Book.title = 'Title of first printing'
- >>> Book.author = 'List of authors sorted by last name'
+ >>> Book.id.__doc__ = '13-digit ISBN'
+ >>> Book.title.__doc__ = 'Title of first printing'
+ >>> Book.author.__doc__ = 'List of authors sorted by last name'
Default values can be implemented by using :meth:`_replace` to
customize a prototype instance: