use strict;
use warnings;

{
	package Cat;
	use Moose;
	
	has name => (
		is  => 'ro',
		isa => 'Str',
	);
	
	__PACKAGE__->meta->make_immutable;
}

{
	package Litter;
	use Moose;
	
	has cats => (
		is  => 'ro',
		isa => 'ArrayRef[Cat]',
	);
	
	__PACKAGE__->meta->make_immutable;
}

my $cat1   = Cat->new(name=>'Garfield');
my $cat2   = Cat->new(name=>'Felix');
my $litter = Litter->new(cats => [$cat1, $cat2, 1]);