def get_comment_smart_book_session(self, book_id=None):
if book_id is None:<EOL><INDENT>raise NullArgument<EOL><DEDENT>raise Unimplemented()<EOL>
Gets the session associated with the comment smart book for the given book.

        arg:    book_id (osid.id.Id): the ``Id`` of the book
        return: (osid.commenting.CommentSmartBookSession) - a
                ``CommentSmartBookSession``
        raise:  NotFound - ``book_id`` not found
        raise:  NullArgument - ``book_id`` is ``null``
        raise:  OperationFailed - unable to complete request
        raise:  Unimplemented - ``supports_comment_smart_book()`` is
                ``false``
        *compliance: optional -- This method must be implemented if
        ``supports_comment_smart_book()`` is ``true``.*