/**
  * @param ElementInterface $element
  *
  * @return string
  */
 private function getPropertyPathAsIndex(ElementInterface $element)
 {
     return sprintf('[%s]', $element->getName());
 }
 /**
  * Adds new element to collection
  *
  * @param ElementInterface $element
  */
 public function add(ElementInterface $element)
 {
     $this->items[$element->getName()] = $element;
 }