$overDue        = new OverDueSpecification();
$noticeSent     = new NoticeSentSpecification();
$inCollection   = new InCollectionSpecification();
 
// example of specification pattern logic chaining
$sendToCollection = $overDue->andX($noticeSent)
                            ->not($inCollection);
 
foreach ($service->getInvoices() as $currentInvoice) {
    if (! $sendToCollection->isSatisfiedBy($currentInvoice)) {
        continue;
    }
    
    $currentInvoice->sendToCollection();
}