Python mixes immutability and mutability in ways that require careful thinking about the problem if you want to write unbuggy code. E.g., does a tuple holding lists allow modification of the member lists? Intuitively, it would seem to me that immutability should cascade, but thinking about tuples as holding a bag of pointers suggests that the lists are still mutable. Anyway.

I generally take the position that if you have to work around something in your language, it's broken. E.g., the virtualenv hack. It's nice to deploy out an exe and not require a whole ecosystem to be install in order to bootstrap it up.

Happy hacking.