code: def _get_coarse_dataset(self, key, info):
          
          angles = self.root.find('.//Tile_Angles')
          if key in ['solar_zenith_angle', 'solar_azimuth_angle']:
              elts = angles.findall(info['xml_tag'] + '/Values_List/VALUES')
              return np.array([[val for val in elt.text.split()] for elt in elts],
                              dtype=np.float)
  
          elif key in ['satellite_zenith_angle', 'satellite_azimuth_angle']:
              arrays = []
              elts = angles.findall(info['xml_tag'] + '[@bandId="1"]')
              for elt in elts:
                  items = elt.findall(info['xml_item'] + '/Values_List/VALUES')
                  arrays.append(np.array([[val for val in item.text.split()] for item in items],
                                         dtype=np.float))
              return np.nanmean(np.dstack(arrays), -1)
          else:
              return
docs: Get the coarse dataset refered to by `key` from the XML data.