Someone else closed issue 7276, but I was thinking of doing so but
wanted to include a pointer to the relevant documentation.  I'm not sure
where that documentation is, but I figured there ought to be a FAQ entry
for it.  And there is, sort of...the first two sections of the
programming faq's 'core language' section.  However, I think that the
way that most people run in to this problem is by getting the
'UnboundLocalError', and so I think the FAQ entry title should mention
that error.  I attach a proposed update to the first section of the core
language section of the programming FAQ.  I'm also going to attach a
copy of the complete entry since it is hard to read in the patch.