[web2py] Wizard Code

[villas]

>From wizard generated code, but a style promoted elsewhere too...

    f,v = request.args(0), request.args(1)
    query = f and db.table[f]==v or db.table

If I use a wrong url e.g. 'function/my/error',  this code fails.

I expected that if  'f and db.table[f]==v'  fails then 'db.table' is
used instead?  A bit like a 'try/excepts'.  This doesn't appear to be
the case.

Therefore this is bad code (unrobust)?  What's the answer, a real try/
excepts or does it just need tweaking?