changes to shelf items fail silently?

[Raymond Hettinger]

> So, I see why the last case works (it can't help *but* work) but I
> don't get why the append/extend mutators don't.  Or rather, why if
> they can't work, I don't get an error thrown so I notice it...
>
> (this occurs in 2.1 and 2.2.  Is there a "better" shelf-like thing
> that I should use instead, for more completely persistent data?)

Yes.
Alex Martelli proposed a solution:
www.python.org/sf/553171


Raymond Hettinger