But you can replace the simple 'lambda' with a function that takes the max with 'columns'.  In other words, include: 

             width = _shutil.get_terminal_size().columns
             width -= 2
             width = min(max_text_width, width)

The only thing that the 'formatter_class' parameter requires is a callable that takes 'prog' as argument.  That can be a class, a subclass, a lambda or a function.