if ( findAncestorWithClass( GuardTag.class ) == null ) { throw new JellyException( "Unable to locate guard" ); }
System.err.println( "PassTag#####doTag()" );
    public void doTag(XMLOutput output) throws Exception    {        if ( findAncestorWithClass( GuardTag.class ) == null )        {            throw new JellyException( "Unable to locate guard" );        }        throw new PassException();    }