def _find_clim_vars(self, ds, refresh=False):
        '''
        Returns a list of variables that are likely to be climatology variables based on CF §7.4

        :param netCDF4.Dataset ds: An open netCDF dataset
        :param bool refresh: if refresh is set to True, the cache is
                             invalidated.
        :rtype: list
        :return: A list containing strings with geophysical variable
                 names.
        '''

        if self._clim_vars.get(ds, None) and refresh is False:
            return self._clim_vars[ds]

        climatology_variable = cfutil.get_climatology_variable(ds)
        if climatology_variable:
            self._clim_vars[ds].append(climatology_variable)

        return self._clim_vars[ds]
Returns a list of variables that are likely to be climatology variables based on CF §7.4

        :param netCDF4.Dataset ds: An open netCDF dataset
        :param bool refresh: if refresh is set to True, the cache is
                             invalidated.
        :rtype: list
        :return: A list containing strings with geophysical variable
                 names.