multi sub clone (Object where { $_->can('clone') } $value) {
    return $value->clone;
}
multi sub clone (Scalar $value) {
    return $value;
}
multi sub clone (ArrayRef $value) {
    return map { clone($_) } @$value;
}
multi sub clone (HashRef $value) {
    return map { $_ => clone( $value->{$_} ) } keys %$value;
}