@utilities.arguments_not_none<EOL><INDENT>def remove_root_book(self, book_id):<DEDENT>
<EOL>if self._catalog_session is not None:<EOL><INDENT>return self._catalog_session.remove_root_catalog(catalog_id=book_id)<EOL><DEDENT>return self._hierarchy_session.remove_root(id_=book_id)<EOL>
Removes a root book.

        arg:    book_id (osid.id.Id): the ``Id`` of a book
        raise:  NotFound - ``book_id`` is not a root
        raise:  NullArgument - ``book_id`` is ``null``
        raise:  OperationFailed - unable to complete request
        raise:  PermissionDenied - authorization failure
        *compliance: mandatory -- This method must be implemented.*