Nothing really. For some reason our textbook author wrote a getCenter() method for Circles, but a getAnchor() method for Images and Text objects, even though it really does return the center point.
I thought it would be more uniform if EVERY shape had a getCenter() method, so I updated that when I created graphics2.py.
However, I didn't remove the getAnchor() method because I wanted to make sure all the book code/examples would still work with graphics2...