code: def _merge_common_bands(rasters):
      # type: (List[_Raster]) -> List[_Raster]
      
      # Compute band order
      all_bands = IndexedSet([rs.band_names[0] for rs in rasters])
  
      def key(rs):
          return all_bands.index(rs.band_names[0])
  
      rasters_final = []  # type: List[_Raster]
      for band_name, rasters_group in groupby(sorted(rasters, key=key), key=key):
          rasters_final.append(reduce(_fill_pixels, rasters_group))
  
      return rasters_final
docs: Combine the common bands.