Thanks so much guys! I'm not planning to prepare for every possible situation, but I certainly am responsible to handle most common errors. So it's really important to know what a function/method returns when called.
Exception handling may take lots of code, but I'm used to it. It's much better to have a graceful shutdown than a data/time loss. ;) I think PEP 3151 is a step ahead! That's almost exactly what I was looking for. Why did it take so long to have that implemented? -- http://mail.python.org/mailman/listinfo/python-list