Get the `postadres` for a :class:`Huisnummer`.

        :param huisnummer: The :class:`Huisnummer` for which the \
            `postadres` is wanted. OR A huisnummer id.
        :rtype: A :class:`str`.

def get_postadres_by_huisnummer(self, huisnummer):
        '''
        Get the `postadres` for a :class:`Huisnummer`.

        :param huisnummer: The :class:`Huisnummer` for which the \
            `postadres` is wanted. OR A huisnummer id.
        :rtype: A :class:`str`.
        '''
        try:
            id = huisnummer.id
        except AttributeError:
            id = huisnummer
        def creator():
            res = crab_gateway_request(
                self.client, 'GetPostadresByHuisnummerId', id
            )
            if res == None:
                 raise GatewayResourceNotFoundException()
            return res.Postadres
        if self.caches['short'].is_configured:
            key = 'GetPostadresByHuisnummerId#%s' % (id)
            postadres = self.caches['short'].get_or_create(key, creator)
        else:
            postadres = creator()
        return postadres