code: def add_option(self, value, label):
          
          if type(value) is list:
              warnings.warn(".add_option() accepts single value now.", DeprecationWarning, stacklevel=1)
              value = value[0]
          if self.type not in ("list-multi", "list-single"):
              raise ValueError("Options are allowed only for list types.")
          option = Option(value, label)
          self.options.append(option)
          return option
docs: Add an option for the field.
  
          :Parameters:
              - `value`: option values.
              - `label`: option label (human-readable description).
          :Types:
              - `value`: `list` of `unicode`
              - `label`: `unicode`