docs: def packfile(filename, srcdir):
      """Package up srcdir into filename, archived with 7z for exes or mar for
      mar files"""
      if filename.endswith(".mar"):
          return packmar(filename, srcdir)
      elif filename.endswith(".exe"):
          return packexe(filename, srcdir)
      elif filename.endswith(".tar"):
          return tar_dir(filename, srcdir)
      else:
          raise ValueError("Unknown file type: %s" % filename)