def industries_using_cargo(self, cargo):
        # segmented by economy
        result = {}
        for economy in self.get_economies_sorted_by_name():
            accepted_by = self.industry_find_industries_active_in_economy_for_cargo(cargo, economy, 'accept_cargo_types')
            produced_by = self.industry_find_industries_active_in_economy_for_cargo(cargo, economy, 'prod_cargo_types')
            if len(list(accepted_by) + list(produced_by)) > 0:
                result[economy] = {'accepted_by':accepted_by, 'produced_by':produced_by}
        return result

    def cargo_unique_industry_combinations(self, cargo):
        result = {}
        for economy in self.get_economies_sorted_by_name():
            economy_industries = []
            accepted_by = self.industry_find_industries_active_in_economy_for_cargo(cargo, economy, 'accept_cargo_types')
            produced_by = self.industry_find_industries_active_in_economy_for_cargo(cargo, economy, 'prod_cargo_types')
            for industry in accepted_by:
                economy_industries.append(industry)
            for industry in produced_by:
                economy_industries.append(industry)
            if len(economy_industries) > 0:
                industry_key = tuple(sorted(economy_industries))
                result.setdefault(industry_key, {'accepted_by': accepted_by, 'produced_by': produced_by})
                result[industry_key].setdefault('economies',[]).append(economy)
                 # convenient to have items sorted
                result[industry_key]['economies'] = sorted(result[industry_key]['economies'], key=lambda economy: self.get_economy_name(economy))
        # return a list, sorted by economies (only need first economy entry in each list of economies)
        return sorted(result.values(), key = lambda combo: self.get_economy_name(combo['economies'][0]))