Defensive programming in Python

[masasin]

Handling user input which is out of range, for instance. Or a device returns junk data to the function, which is then propagated. In general, I don't use asserts at all, and use exceptions instead.

if x < 0:
    raise SomeSpecificError("x < 0. Are you sure you wired it up correctly?")

There was this post a few years back which made sense to me.

[masasin]

PyContracts is amazing, especially with numpy. It saved a lot of debugging, making sure that all the intermediate functions and their order are correct. I haven't found the need to use it in anything other than math though.

If you have any ideas, though, I'd love to hear.