code: def do_create(marfile, files, compress, productversion=None, channel=None,
                signing_key=None, signing_algorithm=None):
      
      with open(marfile, 'w+b') as f:
          with MarWriter(f, productversion=productversion, channel=channel,
                         signing_key=signing_key,
                         signing_algorithm=signing_algorithm,
                         ) as m:
              for f in files:
                  m.add(f, compress=compress)
docs: Create a new MAR file.