/**
  * Adds inherited indexes to the subclass mapping.
  *
  * @param ClassMetadata $subClass
  * @param ClassMetadata $parentClass
  */
 private function addInheritedIndexes(ClassMetadata $subClass, ClassMetadata $parentClass)
 {
     foreach ($parentClass->indexes as $index) {
         $subClass->addIndex($index['keys'], $index['options']);
     }
 }