pattern matching in python

[Quinn Dunkan]

Every once in a while, I remember that python does basic tuple
pattern-matching, which doesn't seem to come up much in the documentation,
except for things like 'a, b = f()'.  Specifically, nested matching, like:

t = [ (1, (2, 3), 4), ]
for (a, (x, y), b) in t: ...

I recently noticed, that, of course,

def f(a, (x, y), b): ...

works too.  Is this standard, documented behaviour that can be relied on?

ok-so-where's-the-cons-operator-ly y'rs