[Edu-sig] Fw: Python sequences by reference - how to make clear

[Guido van Rossum]

What Kirby describes can be had by doing

    >>> from copy import copy, deepcopy

copy() nor deepcopy() is a built-in, because it is a potentially
expensive operation, and I feel that its presence as a built-in would
cause beginning and intermediate programmers to overuse it.

--Guido van Rossum (home page: http://www.python.org/~guido/)