> Because this is an internal function in a _library_ Why does that matter? Error-prone approaches create buggy code and we don't want buggy code, whether it's

> Because this is an internal function in a _library_ Why does that matter? Error-prone approaches create buggy code and we don't want buggy code, whether it's a library or something else. Libraries can be huge and complex, and arguably should have more robust edge case checking than regular code.