code: func (g *Graph) GetFloat64(path string) (float64, error) {
  
  	if len(path) == 0 {
  		return g.Float64(), nil
  	}
  
  	i := g.Get(path)
  	if i == nil {
  		return 0, errors.New("not found")
  	}
  	if i.Len() == 0 {
  		return 0, errors.New("Get() design error: not subnodes")
  	}
  	j, ok := _float64f(i.Out[0].This)
  	if !ok {
  		return 0, errors.New("not a number")
  	}
  	return j, nil
  }
docs: // GetFloat64 returns the result of applying a path to the given Graph.
  // The result is returned as a float64. If the path result cannot be converted
  // to a float, then an error is returned.