code: public static function createFromArray(array $selectedExtras, Product $product) // TODO
      {
          $extras = [];
  
          foreach ($selectedExtras as $extra) {
              list($setId, $extraId) = explode('_', $extra);
  
              $extraSet = $product->getExtraSetByID($setId);
  
              $extras[] = new static($extraSet, $extraSet->getExtraByID($extraId));
          }
  
          return $extras;
      }
docs: @param array   $selectedExtras
  @param Product $product
  
  @return array|static[]