[Closed] How can I get key number which I just add on currentTime

max set key keys
$.transform.controller.LayerTrans.controller.Animation_Layer.controller.Rotation.controller.Z_Rotation.controller.keys[4].value = -45

I want to get number 4 from “Keys[4]”.
I tried to search in Maxscript help and many topics on internet but couldn’t find solution.
Any suggestion?