To make using the progress bar easier for users, it would be nice to have the ability to specify a minimum and maximum value for the control (which represent the values 0% and 100%). This would remove the need to compute the percentage from the user, particularly when their range values don't neatly fit in a 0..1, 0..10, 0..100 and other such "easy" ranges.

Example

progress_bar = ProgressBar(..., min=20, max=50, ...)

# Some work happens . . . 

# Update the progress bar to the new value...
progress_bar.progress = 22  # Let the control figure out "6.67%"

progress_bar.max = 60  # This would NOT be valid. "min" and "max" are fixed at initialization