code: def copy_ccube(ccube, outsrcmap, hpx_order):
          
          sys.stdout.write("  Copying counts cube from %s to %s\n" % (ccube, outsrcmap))
          try:
              hdulist_in = fits.open(ccube)
          except IOError:
              hdulist_in = fits.open("%s.gz" % ccube)
  
          hpx_order_in = hdulist_in[1].header['ORDER']
  
          if hpx_order_in > hpx_order:
              hpxmap = HpxMap.create_from_hdulist(hdulist_in)
              hpxmap_out = hpxmap.ud_grade(hpx_order, preserve_counts=True)
              hpxlist_out = hdulist_in
              #hpxlist_out['SKYMAP'] = hpxmap_out.create_image_hdu()
              hpxlist_out[1] = hpxmap_out.create_image_hdu()
              hpxlist_out[1].name = 'SKYMAP'
              hpxlist_out.writeto(outsrcmap)
              return hpx_order
          else:
              os.system('cp %s %s' % (ccube, outsrcmap))
              #os.system('cp %s.gz %s.gz' % (ccube, outsrcmap))
              #os.system('gunzip -f %s.gz' % (outsrcmap))
          return None
docs: Copy a counts cube into outsrcmap file
          reducing the HEALPix order to hpx_order if needed.