code: def get_temp_tag_for_repo_creation(self):
          
          tag_date = self.tag_times_dict.get(REPO_CREATED_TAG_NAME, None)
          if not tag_date:
              tag_name, tag_date = self.fetcher.fetch_repo_creation_date()
              self.tag_times_dict[tag_name] = timestring_to_datetime(tag_date)
          return REPO_CREATED_TAG_NAME
docs: If not already cached, fetch the creation date of the repo, cache it
          and return the special value indicating the creation of the repo.
  
          :rtype: str
          :return: value indicating the creation