package Animal;
use Class::Std;
{
    sub speak : CUMULATIVE(BASE FIRST) {
        my $self = shift;
        print 'A ', ref $self, ' goes ', $self->get_sound() . "\n";
    }
}
1;

package Danger;
use Class::Std;
{
    sub speak : CUMULATIVE(BASE FIRST) {
        my $self = shift;
        print 'through an eye patch ...' . "\n";
    }
}
1;

package Mouse;
use Class::Std;
use base qw(Animal Danger);
{
    my %sound : ATTR( :name<sound>, :default<squeek> );
    sub speak : CUMULATIVE(BASE FIRST) {
        my $self = shift;
        print '[but you can barely hear it!]' . "\n";
    }
}
1;