code: func (it *Resolver) Contains(ctx context.Context, value graph.Value) bool {
  	graph.ContainsLogIn(it, value)
  	if !it.cached {
  		it.err = it.resolve(ctx)
  		if it.err != nil {
  			return false
  		}
  	}
  	_, ok := it.nodes[value.Key()]
  	return graph.ContainsLogOut(it, value, ok)
  }
docs: // Check if the passed value is equal to one of the order stored in the iterator.