@utilities.arguments_not_none<EOL><INDENT>def order_by_cumulative_rating(self, book_id, style):<DEDENT>
raise errors.Unimplemented()<EOL>
Orders by the cumulative rating in a given ``Book``.

        arg:    book_id (osid.id.Id): a book ``Id``
        arg:    style (osid.SearchOrderStyle): search order style
        raise:  NullArgument - ``book_id`` or ``style`` is ``null``
        *compliance: mandatory -- This method must be implemented.*