sub _create_node
  {
    my ($node,$parent,$node_info) = @_;
    no strict;
    @{$node}{qw/parent info/} = ($parent,$node_info);
  }

##</code><code>##

sub go_through
  {
    no strict 'refs';
    my ($self, $node) = @_;
    return "" unless defined ${$node}{"info"};
    my @info_nodes;
    while (${$node}{"info"} ne "root"){
      push @info_nodes, (${$node}{"info"});
      $node = ${$node}{"parent"};
    }
    return \@info_nodes;
  }