code: def update_hpx_skymap_allsky(map_in, map_out):
      
      if map_out is None:
          in_hpx = map_in.hpx
          out_hpx = HPX.create_hpx(in_hpx.nside, in_hpx.nest, in_hpx.coordsys,
                                   None, in_hpx.ebins, None, in_hpx.conv, None)
          data_out = map_in.expanded_counts_map()
          print(data_out.shape, data_out.sum())
          map_out = HpxMap(data_out, out_hpx)
      else:
          map_out.data += map_in.expanded_counts_map()
      return map_out
docs: 'Update' a HEALPix skymap
  
      This checks map_out exists and creates it from map_in if it does not.
      If map_out does exist, this adds the data in map_in to map_out