code: def _get_data_raw(self, time, site_id):
          
          path = ('?region=naconf&TYPE=TEXT%3ALIST'
                  '&YEAR={time:%Y}&MONTH={time:%m}&FROM={time:%d%H}&TO={time:%d%H}'
                  '&STNM={stid}').format(time=time, stid=site_id)
  
          resp = self.get_path(path)
          # See if the return is valid, but has no data
          if resp.text.find('Can\'t') != -1:
              raise ValueError(
                  'No data available for {time:%Y-%m-%d %HZ} '
                  'for station {stid}.'.format(time=time, stid=site_id))
  
          return resp.text
docs: Download data from the University of Wyoming's upper air archive.
  
          Parameters
          ----------
          time : datetime
              Date and time for which data should be downloaded
          site_id : str
              Site id for which data should be downloaded
  
          Returns
          -------
          text of the server response