code: def hourly_solar_radiation(self):
          
          dir_norm, diff_horiz, glob_horiz = \
              self._sky_condition.radiation_values(self._location)
  
          dir_norm_data = self._get_daily_data_collections(
              energyintensity.DirectNormalRadiation(), 'Wh/m2', dir_norm)
          diff_horiz_data = self._get_daily_data_collections(
              energyintensity.DiffuseHorizontalRadiation(), 'Wh/m2', diff_horiz)
          glob_horiz_data = self._get_daily_data_collections(
              energyintensity.GlobalHorizontalRadiation(), 'Wh/m2', glob_horiz)
  
          return dir_norm_data, diff_horiz_data, glob_horiz_data
docs: Three data collections containing hourly direct normal, diffuse horizontal,
          and global horizontal radiation.