The main issue, as I noted, is people who come from other languages and have preconceived notions about what "pass by value" and "pass by reference" mean and pr

The main issue, as I noted, is people who come from other languages and have preconceived notions about what "pass by value" and "pass by reference" mean and preconceived expectations about language behavior as a result. In Python, worrying about whether it's "pass-by-X" paradigm is practically worthless; instead, what you want to know in Python is which types are mutable.