code: func (it *LinksTo) Close() error {
  	err := it.nextIt.Close()
  
  	_err := it.primaryIt.Close()
  	if _err != nil && err == nil {
  		err = _err
  	}
  
  	return err
  }
docs: // Close closes the iterator.  It closes all subiterators it can, but
  // returns the first error it encounters.