- self.outfile.write(ind_s*(level+1) + '<DT><A HREF="%s" ADD_DATE="%s" LAST_VISIT="%s" LAST_MODIFIED="%s"' % (b.href, b.add_date, b.last_visit, b.last_modified))
+ self.outfile.write(ind_s*(level+1) + '<DT><A HREF="%s" ADD_DATE="%s"' % (b.href, b.add_date))
+ if b.last_visit: self.outfile.write(' LAST_VISIT="%s"' % b.last_visit)
+ self.outfile.write(' LAST_MODIFIED="%s"' % b.last_modified)