code: def chmod_plus(path, add_bits=stat.S_IWUSR):
      
      try:
          os.chmod(path, stat.S_IMODE(os.stat(path).st_mode) | add_bits)
      except OSError:  # pragma: nocover
          pass
docs: Change a file's mode by adding a few bits.
  
      Like chmod +<bits> <path> in a Unix shell.