They're required positional args, here's what they turn into in usage:
```text
usage: update_rhel.py [-h] [--reboot] address repo_url

positional arguments:
  address     hostname or ip address of target appliance
  repo_url    updates base url

optional arguments:
  -h, --help  show this help message and exit
  --reboot    reboot after installation (required for proper operation)

```