protected function notify(ObservationContainerInterface $container): ? ObservationContainerInterface
    {
        foreach ( $this->observers as $current ) {
            $current->update($container);
        }

        return $container;
    }
protected function notify(ObservationContainerInterface $container): ? ObservationContainerInterface
    {
        foreach ( $this->observers as $current ) {
            $current->update($container);
        }

        return $container;
    }
protected function notify ( ObservationContainerInterface $ container ) : ? ObservationContainerInterface { foreach ( $ this -> observers as $ current ) { $ current -> update ( $ container ) ; } return $ container ; }
notifies all observers using a observation container implementation.

@param ObservationContainerInterface $container
@return ObservationContainerInterface|null
notifies all observers using a observation container implementation .