- treat restricted/reserved TLDs (invalid, test, example, localhost)
          as invalid (thanks, Steve Bertrand!)


# Purpose: Check whether a top level domain is valid for a domain.
sub tld {
  my $self = shift;
  my %args = $self->_rearrange([qw( address )], \@_);
 
  unless (eval {require Net::Domain::TLD; Net::Domain::TLD->VERSION(1.65); 1}) {
    die "Net::Domain::TLD not available";
  }
 
  my $host = $self->_host( $args{address} or return $self->details('tld') );
  my ($tld) = $host =~ m#\.(\w+)$#;
 
  my %invalid_tlds = map { $_ => 1 } qw(invalid test example localhost);
 
  return defined $invalid_tlds{$tld} ? 0 : Net::Domain::TLD::tld_exists($tld);
}