def set_ocha_url(cls, url=None):
        # type: (str) -> None
        """
        Set World Bank url from which to retrieve countries data

        Args:
            url (str): World Bank url from which to retrieve countries data. Defaults to internal value.

        Returns:
            None
        """
        if url is None:
            url = cls._ochaurl_int
        cls._ochaurl = url