That lambda function would not give the same result, as it would constrain the text width to a fixed value, while my proposal would just set a maximum limit (if the terminal is narrower, the actual text width would be reduced).

With the current implementation all possible solutions are in my opinion overkilling for such a basic task. Maybe it is not a direct consequence of this, but as a matter of fact most Python scripts using `argparse` that I know (including `pip`) do not control the text width, which IMHO is not a good practice.