code: def country_code_by_addr(self, addr):
          
          VALID_EDITIONS = (const.COUNTRY_EDITION, const.COUNTRY_EDITION_V6)
          if self._databaseType in VALID_EDITIONS:
              country_id = self.id_by_addr(addr)
              return const.COUNTRY_CODES[country_id]
          elif self._databaseType in const.REGION_CITY_EDITIONS:
              return self.region_by_addr(addr).get('country_code')
  
          raise GeoIPError('Invalid database type, expected Country, City or Region')
docs: Returns 2-letter country code (e.g. US) from IP address.
  
          :arg addr: IP address (e.g. 203.0.113.30)