如何在Perl和Moose中创建不可变对象的循环图？

cpan install Moose
cpan install MooseX::NonMutable

use strict;
use warnings;
use Moose;
use MooseX::NonMutable;

{
    package Node;
    use Moose;
    use MooseX::NonMutable;

    has 'name' => (
        is => 'ro',
        isa => 'Str',
    );

    has 'children' => (
        is => 'ro',
        isa => 'ArrayRef[Node]',
        traits => ['Array'],
        handles => {
            add_child => 'push',
            all_children => 'elements',
        },
    );

    immutable;
}

my $node1 = Node->new(name => 'Node 1');
my $node2 = Node->new(name => 'Node 2');
my $node3 = Node->new(name => 'Node 3');

$node1->add_child($node2);
$node2->add_child($node3);
$node3->add_child($node1);