code: func (g *Graph) GetBool(path string) (bool, error) {
  
  	if len(path) == 0 {
  		return g.Bool(), nil
  	}
  
  	i := g.Get(path)
  	if i == nil {
  		return false, errors.New("not found")
  	}
  	if i.Len() == 0 {
  		return false, errors.New("Get() design error: not subnodes")
  	}
  	j, ok := _boolf(i.Out[0].This)
  	if !ok {
  		return false, errors.New("not a boolean")
  	}
  	return j, nil
  }
docs: // GetBool returns the result of applying a path to the given Graph.
  // The result is returned as a bool. If the path result cannot be converted
  // to a boolean, then an error is returned.