The course is using Python to implement a Scheme, then uses Scheme to implement a Scheme. Python could and should be removed from the course.
Python has very poor support for functional programming. Lists are not cons based, lambdas are crippled, pattern matching is horrible and not even expression based, namespaces are weird.
Python is not even a current language, it is stuck in the 1990s and happens to have a decent C-API that unfortunately fueled its growth at the expense of better languages.