Iterate through nations ranked on the World Census scale.

        If the ranks change while you interate over them, they may be
        inconsistent.

        Parameters
        ----------
        scale : int
            A World Census scale, an integer between 0 and 85 inclusive.

        Returns
        -------
        asynchronous iterator of :class:`CensusRank`

async def censusranks(self, scale):
        """Iterate through nations ranked on the World Census scale.

        If the ranks change while you interate over them, they may be
        inconsistent.

        Parameters
        ----------
        scale : int
            A World Census scale, an integer between 0 and 85 inclusive.

        Returns
        -------
        asynchronous iterator of :class:`CensusRank`
        """
        order = count(1)
        for offset in count(1, 20):
            census_ranks = await self._get_censusranks(
                scale=scale, start=offset)
            for census_rank in census_ranks:
                assert census_rank.rank == next(order)
                yield census_rank
            if len(census_ranks) < 20:
                break