[IronPython] How do I test if a variable is defined?

[Tony Meyer]

>> If you're running some sort of checker (pylint, pychecker) over this,
>> you might get a warning about the "name" line not doing anything.  To
>> avoid that, you'll sometimes see a variant like this:
>>
>> try:
>>    unused = name
>> except NameError:
>>    # variable 'name' is not defined.
>>
>
> Except then PyLint will complain that 'unused' is unused, plus you code no
> longer accurately conveys its intent.

Well pychecker ignores variables called "unused" (and _, but that
clashes with the gettext usage).  I figured pylint did too, but that
was only a guess.  IMO this code does accurately convey its intent - I
have seen this idiom in a lot of Python code.

Cheers,
Tony