It's the Arizona Constitution. Which means it's the law in Arizona since 1912.

I just randomly picked another state and here's how the process works in Montana.

https://leg.mt.gov/bills/mca/Constitution/VI/14.htm

Here's Mississippi https://ballotpedia.org/Article_V,_Mississippi_Constitution#Section_131

Lots of states have these rules when the governor leaves the state.

It's the Arizona Constitution. Which means it's the law in Arizona since 1912.

I just randomly picked another state and here's how the process works in Montana.