Comment 35 for bug 1992679

@Alberto Milone (albertomilone):

sudo apt-get --purge remove '*nvidia*'

removed a lot of packages except these:

```
$ dpkg -l | awk '/nvidia/{ print $2 }'
libnvidia-compute-515:i386
libnvidia-decode-515:i386
libnvidia-encode-515:i386
libnvidia-fbc1-515:i386
```

```
$ sudo ubuntu-drivers install
Traceback (most recent call last):
  File "/usr/bin/ubuntu-drivers", line 513, in <module>
    greet()
  File "/usr/lib/python3/dist-packages/click/core.py", line 1128, in __call__
    return self.main(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/click/core.py", line 1053, in main
    rv = self.invoke(ctx)
  File "/usr/lib/python3/dist-packages/click/core.py", line 1659, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/usr/lib/python3/dist-packages/click/core.py", line 1395, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/usr/lib/python3/dist-packages/click/core.py", line 754, in invoke
    return __callback(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/click/decorators.py", line 84, in new_func
    return ctx.invoke(f, obj, *args, **kwargs)
  File "/usr/lib/python3/dist-packages/click/core.py", line 754, in invoke
    return __callback(*args, **kwargs)
  File "/usr/bin/ubuntu-drivers", line 413, in install
    command_install(config)
  File "/usr/bin/ubuntu-drivers", line 187, in command_install
    UbuntuDrivers.detect.nvidia_desktop_pre_installation_hook(to_install)
  File "/usr/lib/python3/dist-packages/UbuntuDrivers/detect.py", line 839, in nvidia_desktop_pre_installation_hook
    with_nvidia_kms = version >= 470
UnboundLocalError: local variable 'version' referenced before assignment
```

looks like this try is failing with a ValueError so the version var is not assigned:

```
$ grep 'Enable KMS if nvidia >= 470' -A 8 /usr/lib/python3/dist-packages/UbuntuDrivers/detect.py
    # Enable KMS if nvidia >= 470
    for package_name in to_install:
        if package_name.startswith('nvidia-driver-'):
            try:
                version = int(package_name.split('-')[-1])
            except ValueError:
                pass
            finally:
                with_nvidia_kms = version >= 470
```