src/Model.php
public final function attach(ObserverInterface $observer): SubjectInterface
   {
       if ($observer instanceof ViewInterface) {
           parent::attach($observer);
       }
       return $this;
   }
public final function attach(ObserverInterface $observer): SubjectInterface
   {
       if ($observer instanceof ViewInterface) {
           parent::attach($observer);
       }
       return $this;
   }
{@inheritDoc}
@see \Seeren\View\Observer\AbstractSubject::attach()