Run time default arguments

[ting at thsu.org]

What is the most common way to handle default function arguments that
are set at run time, rather than at compile time? The snippet below is
the current technique that I've been using, but it seems inelegant.

defaults = { 'debug' : false }
def doSomething (debug = None):
    debug = debug if debug != None else defaults['debug']
    # blah blah blah

Basically, I want to define a set of common defaults at the module and/
or class level but let them be overridden via function arguments. The
simpler, naive approach does not work, because the argument gets set
at compile time, rather than at run time. That is:
    def doSomething(debug = defaults['debug'])
ends up being compiled into:
    def doSomething(debug = false)
which is not the behavior I want, as I want to evaluate the argument
at run time.

Any better suggestions?
--
// T.Hsu