docs: def _add_countriesdata(cls, iso3, country):
          # type: (str, hxl.Row) -> None
          """
          Set up countries data from data in form provided by UNStats and World Bank
  
          Args:
              iso3 (str): ISO3 code for country
              country (hxl.Row): Country information
  
          Returns:
              None
          """
          countryname = country.get('#country+name+preferred')
          cls._countriesdata['countrynames2iso3'][countryname.upper()] = iso3
          iso2 = country.get('#country+code+v_iso2')
          if iso2:
              cls._countriesdata['iso2iso3'][iso2] = iso3
              # different types so keys won't clash
              cls._countriesdata['iso2iso3'][iso3] = iso2
          m49 = country.get('#country+code+num+v_m49')
          if m49:
              m49 = int(m49)
              cls._countriesdata['m49iso3'][m49] = iso3
              # different types so keys won't clash
              cls._countriesdata['m49iso3'][iso3] = m49
          cls._countriesdata['aliases'][iso3] = re.compile(country.get('#country+regex'), re.IGNORECASE)
          regionname = country.get('#region+main+name+preferred')
          sub_regionname = country.get('#region+sub+name+preferred')
          intermediate_regionname = country.get('#region+intermediate+name+preferred')
          regionid = country.get('#region+main+code')
          if regionid:
              regionid = int(regionid)
          sub_regionid = country.get('#region+sub+code')
          if sub_regionid:
              sub_regionid = int(sub_regionid)
          intermediate_regionid = country.get('#region+intermediate+code')
          if intermediate_regionid:
              intermediate_regionid = int(intermediate_regionid)
  
          # region, subregion and intermediate region codes do not clash so only need one dict
          def add_country_to_set(colname, idval, iso3):
              value = cls._countriesdata[colname].get(idval)
              if value is None:
                  value = set()
                  cls._countriesdata['regioncodes2countries'][idval] = value
              value.add(iso3)
  
          if regionname:
              add_country_to_set('regioncodes2countries', regionid, iso3)
              cls._countriesdata['regioncodes2names'][regionid] = regionname
              cls._countriesdata['regionnames2codes'][regionname.upper()] = regionid
          if sub_regionname:
              add_country_to_set('regioncodes2countries', sub_regionid, iso3)
              cls._countriesdata['regioncodes2names'][sub_regionid] = sub_regionname
              cls._countriesdata['regionnames2codes'][sub_regionname.upper()] = sub_regionid
          if intermediate_regionname:
              add_country_to_set('regioncodes2countries', intermediate_regionid, iso3)
              cls._countriesdata['regioncodes2names'][intermediate_regionid] = intermediate_regionname
              cls._countriesdata['regionnames2codes'][intermediate_regionname.upper()] = \
                  intermediate_regionid