A corollary or generalized interpretation of this approach (and someone please specify if there’s a formal term for this) is: “fail locally, and immediately.”

What I mean is that once something unexpected happens your code should ideally fail in that step itself.

The simplest most common example I’ve seen with python programmers is when they pass around dicts as arguments in complex code bases. Methods expect various keys to be present, and often methods also have fail safe defaults if some keys are absent. The defaults are written for the specification, sure, but often they also tolerate unexpected exceptions that happened upstream.

Now when an unexpected exception happens, your program fails somewhere else and the stacktrace is useless. The only way to figure out what went wrong is to debug it line by line.

With python there’s still no elegant solution. I’m now trying to ensure all my methods are typed and use dataclasses and pydantic classes to type and group these parameters but there’s still opportunities for these “fail later” errors. Solutions and suggestions would be appreciated!