docs: def list_secties_by_afdeling(self, afdeling):
          '''
          List all `secties` in a `kadastrale afdeling`.
  
          :param afdeling: The :class:`Afdeling` for which the `secties` are \
              wanted. Can also be the id of and `afdeling`.
          :rtype: A :class:`list` of `Sectie`.
          '''
          try:
              aid = afdeling.id
              gid = afdeling.gemeente.id
          except AttributeError:
              aid = afdeling
              afdeling = self.get_kadastrale_afdeling_by_id(aid)
              gid = afdeling.gemeente.id
          afdeling.clear_gateway()
  
          def creator():
              url = self.base_url + '/municipality/%s/department/%s/section' % (gid, aid)
              h = self.base_headers
              res = capakey_rest_gateway_request(url, h).json()
              return [
                  Sectie(
                      r['sectionCode'],
                      afdeling
                  ) for r in res['sections']
              ]
  
          if self.caches['long'].is_configured:
              key = 'list_secties_by_afdeling_rest#%s' % aid
              secties = self.caches['long'].get_or_create(key, creator)
          else:
              secties = creator()
          for s in secties:
              s.set_gateway(self)
          return secties