code: def _add_user_from_conv_part(self, conv_part):
          
          user_ = User.from_conv_part_data(conv_part, self._self_user.id_)
  
          existing = self._user_dict.get(user_.id_)
          if existing is None:
              logger.warning('Adding fallback User with %s name "%s"',
                             user_.name_type.name.lower(), user_.full_name)
              self._user_dict[user_.id_] = user_
              return user_
          else:
              existing.upgrade_name(user_)
              return existing
docs: Add or upgrade User from ConversationParticipantData.