SageMath (originally Sage) is a computer algebra system that is built on top of Python, which is a popular general-purpose programming language. In this appendix we highlight a few features of Python through a series of SageMath cells. Pure Python code can generally be evaluated in these cells and most of what you see here is just Python. There are exceptions. For example, SageMath has enhanced capabilities to work with sets. In Python, the expression set([0,1,2,3]) is a set of four integers, and certain basic set operations can be performed on these types of expressions. This is a valid expression in SageMath too, but a different SageMath expression, Set([0,1,2,3]), with a capital S, has enhanced properties. For example, we can create the power set of the SageMath expression, which we do in the discussion of iterators.
