Convert cloud cover to irradiance. A wrapper method.

        Parameters
        ----------
        cloud_cover : Series
        how : str, default 'clearsky_scaling'
            Selects the method for conversion. Can be one of
            clearsky_scaling or liujordan.
        **kwargs
            Passed to the selected method.

        Returns
        -------
        irradiance : DataFrame
            Columns include ghi, dni, dhi

def cloud_cover_to_irradiance(self, cloud_cover, how='clearsky_scaling',
                                  **kwargs):
        """
        Convert cloud cover to irradiance. A wrapper method.

        Parameters
        ----------
        cloud_cover : Series
        how : str, default 'clearsky_scaling'
            Selects the method for conversion. Can be one of
            clearsky_scaling or liujordan.
        **kwargs
            Passed to the selected method.

        Returns
        -------
        irradiance : DataFrame
            Columns include ghi, dni, dhi
        """

        how = how.lower()
        if how == 'clearsky_scaling':
            irrads = self.cloud_cover_to_irradiance_clearsky_scaling(
                cloud_cover, **kwargs)
        elif how == 'liujordan':
            irrads = self.cloud_cover_to_irradiance_liujordan(
                cloud_cover, **kwargs)
        else:
            raise ValueError('invalid how argument')

        return irrads