docs: def add_text(self, text, label=None):
          """stub"""
          if label is None:
              label = self._label_metadata['default_string_values'][0]
          else:
              if not self.my_osid_object_form._is_valid_string(
                      label, self.get_label_metadata()) or '.' in label:
                  raise InvalidArgument('label')
          if text is None:
              raise NullArgument('text cannot be none')
          if not (self.my_osid_object_form._is_valid_string(
                  text, self.get_text_metadata()) or isinstance(text, DisplayText)):
              raise InvalidArgument('text')
          if utilities.is_string(text):
              self.my_osid_object_form._my_map['texts'][label] = {
                  'text': text,
                  'languageTypeId': str(DEFAULT_LANGUAGE_TYPE),
                  'scriptTypeId': str(DEFAULT_SCRIPT_TYPE),
                  'formatTypeId': str(DEFAULT_FORMAT_TYPE)
              }
          else:
              self.my_osid_object_form._my_map['texts'][label] = {
                  'text': text.text,
                  'languageTypeId': str(text.language_type),
                  'scriptTypeId': str(text.script_type),
                  'formatTypeId': str(text.format_type)
              }