def alliance(self) -> Union[EveAllianceInfo, None]:
        """
        Pseudo foreign key from alliance_id to EveAllianceInfo
        :raises: EveAllianceInfo.DoesNotExist
        :return: EveAllianceInfo or None
        """
        if self.alliance_id is None:
            return None
        return EveAllianceInfo.objects.get(alliance_id=self.alliance_id)