public function is(Hierarchy $element)
    {
        if (get_class($this) !== get_class($element))
            return false;
        return $this->id === $element->id;
    }
public function is(Hierarchy $element)
    {
        if (get_class($this) !== get_class($element))
            return false;
        return $this->id === $element->id;
    }
public function is ( Hierarchy $ element ) { if ( get_class ( $ this ) !== get_class ( $ element ) ) return false ; return $ this -> id === $ element -> id ; }
Check if the objects are referring to the same element.
@return boolean True if both elements are the same class and ID, false otherwise
Check if the objects are referring to the same element .