code: func (it *Or) subItsContain(ctx context.Context, val graph.Value) (bool, error) {
  	var subIsGood = false
  	for i, sub := range it.internalIterators {
  		subIsGood = sub.Contains(ctx, val)
  		if subIsGood {
  			it.currentIterator = i
  			break
  		}
  
  		err := sub.Err()
  		if err != nil {
  			return false, err
  		}
  	}
  	return subIsGood, nil
  }
docs: // Checks a value against the iterators, in order.