Hi Norma,
As we discussed in our last meeting, the old cmp method does not work for comparison operators in python3 anymore.

So I have added the "total_ordering" decorator to the class definition in file "Object-oriented programming in Python.ipynb" at input line:
In [142].

However this raises the question of how should be explained to students about decorators. Since you are giving the talk, I suppose you have final say in this matter.

Best,
Deb