my $xml_ns = {
"http://perlmonks.org" => prefix,
"http://perlmonks.org/blah" => prefix2
};
my $trigger = "prefix:monastery/prefix:foo/prefix2:bar/prefix2:monk";
my $twig = XML::Twig->new(
  map_xmlns => $xml_ns,
  TwigHandlers => { $trigger => \&function }
);