docs: def add_choice(self, choice, name='', identifier=None):
          """stub"""
          if not isinstance(choice, DisplayText):
              raise InvalidArgument('choice is not a displayText object')
          if identifier is None:
              identifier = str(ObjectId())
          current_identifiers = [c['id'] for c in self.my_osid_object_form._my_map['choices']]
          if identifier not in current_identifiers:
              choice = {
                  'id': identifier,
                  'texts': [self._dict_display_text(choice)],
                  'name': name
              }
              self.my_osid_object_form._my_map['choices'].append(choice)
          else:
              for current_choice in self.my_osid_object_form._my_map['choices']:
                  if current_choice['id'] == identifier:
                      self.add_or_replace_value('texts', choice, dictionary=current_choice)
                      choice = current_choice
          return choice