That's usually a sign of overly aggressive linters and static analyzers. They probably got a "no magic numbers" diagnostic.

The solution to this problem is to add some sort of `NOLINT` comment to that line or, if possible, the comment that turns off that particular check. Then you link to the design document describing what "arr" is and how its interface involves accessing indices 0 and 1.

Or you could wrap "arr" up in a class or function of some sort so the code is theoretically more self documenting.