Rendering “indeterminate” progress bars in the terminal using Python

I have just hit on the "indeterminate" progress bar issue in a new open source app (which is also an example program for a new chapter I am writing for my Common Lisp book): when automating fetching and analyzing information, it is hard to predict how many steps will be taken to normalize the 0 to 100% nature of a progress bar.

I thought of flipping the color and restarting at 0%, but ended up scaling down the amount of progress so any operation usually finishes way before the progress bar goes to 100%.