string.templatelib is a new module in the standard library for Python 3.14 that holds the types we need: Template for the type hint to the function, and Interpolation to check the elements we ...

This tells Python to import SymPy into the main namespace, define a symbolic x variable, and set up "pretty printing." This will make the output look more like it does in a math textbook.

Ok so technically Python is call-by-object and how it behaves depends on what you're doing. The 1st case below behaves like pass-by-value as expected.