code: private <E> List<E> fetch(Class<E> entityClass, Key[] nativeKeys) {
      try {
        List<Entity> nativeEntities = nativeReader.fetch(nativeKeys);
        List<E> entities = DatastoreUtils.toEntities(entityClass, nativeEntities);
        entityManager.executeEntityListeners(CallbackType.POST_LOAD, entities);
        return entities;
      } catch (DatastoreException exp) {
        throw new EntityManagerException(exp);
      }
    }
docs: Fetches a list of entities for the given native keys.
  
  @param entityClass
  the expected result type
  @param nativeKeys
  the native keys of the entities
  @return the list of entities. If one or more keys do not exist, the corresponding item in the
  returned list will be <code>null</code>.