@abc.abstractmethod<EOL><INDENT>def delete_floatingip_precommit(self, context, fip_context):<DEDENT>
pass<EOL>
Perform operations specific to the routertype in preparation for
        the deletion of a floatingip.

        :param context: the neutron context of the request
        :param fip_context: FloatingipContext instance describing the current
                            state of the floatingip, prior to the call to
                            delete it.

        Delete floatingip resources previously allocated by this routertype
        driver for a floatingip. Called inside transaction context on session.
        Runtime errors are not expected, but raising an exception will result
        in rollback of the transaction.