def delete_security_group(self, context, id):
        """Delete chains for Neutron security group."""
        LOG.info(_("MidonetPluginV2.delete_security_group called: id=%s"), id)

        sg = super(MidonetPluginV2, self).get_security_group(context, id)
        if not sg:
            raise ext_sg.SecurityGroupNotFound(id=id)

        if sg["name"] == 'default' and not context.is_admin:
            raise ext_sg.SecurityGroupCannotRemoveDefault()

        with context.session.begin(subtransactions=True):
            super(MidonetPluginV2, self).delete_security_group(context, id)
            self.api_cli.delete_security_group(id)

        LOG.info(_("MidonetPluginV2.delete_security_group exiting: id=%r"), id)