Function attributes: a bug?

[Jeff Epler]

Unfortunately, pychecker does not currently detect this mistake.  However,
it will detect it when nested scopes are not used:

1 def f(arg=[]): 
2         arg.append("zyxxy")

mutabledefarg.py:2: Modifying parameter (arg) with a default value may have
unexpected consequences

The "bug" has nothing to do with function attributes, as many others have
pointed out already.

Jeff