code: def overwrite_fits(hdulist, filename):
      
  
      assert isinstance(hdulist, (fits.HDUList, fits.PrimaryHDU))
      temp_name = None
      flag_delete_temp = False
      if os.path.isfile(filename):
          # PyFITS does not overwrite file
          temp_name = a99.rename_to_temp(filename)
      try:
          hdulist.writeto(filename, output_verify='warn')
          flag_delete_temp = temp_name is not None
      except:
          # Writing failed, reverts renaming
          os.rename(temp_name, filename)
          raise
  
      if flag_delete_temp:
          os.unlink(temp_name)
docs: Saves a FITS file. Combined file rename, save new, delete renamed for FITS files
      Why: HDUlist.writeto() does not overwrite existing files
      Why(2): It is also a standardized way to save FITS files