code: func (f *Form) AddFormItem(item FormItem) *Form {
  	f.items = append(f.items, item)
  	return f
  }
docs: // AddFormItem adds a new item to the form. This can be used to add your own
  // objects to the form. Note, however, that the Form class will override some
  // of its attributes to make it work in the form context. Specifically, these
  // are:
  //
  //   - The label width
  //   - The label color
  //   - The background color
  //   - The field text color
  //   - The field background color