argv parsing in 5.x to pass a set, how to

After upgrading to 5.x I can no longer use the command I once was with voila - after having read through other issues and the docs I see the parsing has changed.
https://github.com/voila-dashboards/voila/issues/813

The difficulty I am running into - is I don't see how to pass a set as an option?

For example, I used to use:
```
voila --no-browser --ExecutePreprocessor.timeout=300 --theme=dark --TagRemovePreprocessor.remove_cell_tags='{"hide"}'
```

but I get the below error when opening notebooks with voila:
```
Jan 21 16:56:38 abc-123-086427 voila[2580]: File "/home/ubuntu/miniconda3/envs/data_analysis_lab/lib/python3.8/site-packages/traitlets/traitlets.py", line 610, in _validate
Jan 21 16:56:38 abc-123-086427 voila[2580]: value = self.validate(obj, value)
Jan 21 16:56:38 abc-123-086427 voila[2580]: File "/home/ubuntu/miniconda3/envs/data_analysis_lab/lib/python3.8/site-packages/traitlets/traitlets.py", line 2496, in validate
Jan 21 16:56:38 abc-123-086427 voila[2580]: value = super(Container, self).validate(obj, value)
Jan 21 16:56:38 abc-123-086427 voila[2580]: File "/home/ubuntu/miniconda3/envs/data_analysis_lab/lib/python3.8/site-packages/traitlets/traitlets.py", line 1845, in validate
Jan 21 16:56:38 abc-123-086427 voila[2580]: self.error(obj, value)
Jan 21 16:56:38 abc-123-086427 voila[2580]: File "/home/ubuntu/miniconda3/envs/data_analysis_lab/lib/python3.8/site-packages/traitlets/traitlets.py", line 690, in error
Jan 21 16:56:38 abc-123-086427 voila[2580]: raise TraitError(e)
Jan 21 16:56:38 abc-123-086427 voila[2580]: traitlets.traitlets.TraitError: The 'remove_cell_tags' trait of a TagRemovePreprocessor instance expected a set, not the str '{"hide"}'.
Jan 21 16:56:38 abc-123-086427 voila[2580]: ERROR:tornado.access:500 GET /voila/render/beta/BSR/Computational_Thinking/what_is_an_algorithm.ipynb (::1) 204.10ms
```

So for `--TagRemovePreprocessor.remove_cell_tags` the error is now saying it is expecting a `set` and not a `str`

I have tried many combinations such as:
```
voila --no-browser --ExecutePreprocessor.timeout=300 --theme=dark --TagRemovePreprocessor.remove_cell_tags=hide
```

Searching through cli options in argparse I don't see a way to pass a `set` from the cli that `TagRemovePreprocessor.remove_cell_tags` is expecting.