code: func (f *Form) GetFormItemIndex(label string) int {
  	for index, item := range f.items {
  		if item.GetLabel() == label {
  			return index
  		}
  	}
  	return -1
  }
docs: // GetFormItemIndex returns the index of the first form element with the given
  // label. If no such element is found, -1 is returned. Buttons are not searched
  // and will therefore not be returned.