sub find
{
  my $tree = shift;
  my $node_value=shift;
  my @childs=();
  my $func;
  $func = sub ($)
  {
    my $child=shift();
    push(@childs,$child) if($child->getNodeValue() eq $node_value);
    my @children=$child->getAllChildren();
    $func->(shift(@children)) while(@children);
  };
  $func->($tree);
  return @childs;
}