gistfile1.pl

{
    package Person::Child;
    use base 'Person';
    __PACKAGE__->attributes('parent');
}

my $child = Person::Child->new();
ok $child->parent($p), 'setting parent';
ok $child->name('bob'), 'setting child name';
ok $child->age(5), 'setting child age';

is $child->age, 5, 'age is ok';
is $child->parent->sex, 'male', 'age is ok';
my $child_attrs = Person::Child->get_attributes();
is_deeply $child_attrs, ['parent', 'name', 'age', 'sex'], "attributes are ok";