I think this is a bug in the last extra test

index_power([75,68,35,61,9,36,89,0,30],10)

There is no 10 index in the list, so -1 is returned. Under the conditions, we raise -1 to the power of 10 and get 1. But the check gives an error and says that it should be -1.

I checked on the calculator and this should be 1.