Slice and Splice Error

Tell us what’s happening:
This code is giving the right output but not being accepted. What am I doing wrong?

Your code so far

function frankenSplice(arr1, arr2, n) {
  // It's alive. It's alive!
  let arr3 =[];
  arr3 = arr2.slice();

frankenSplice([1, 2], ["a", "b"], 1);

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:64.0) Gecko/20100101 Firefox/64.0.

Check browser console, arr3 has subarrays. Also, you need to return it, not just printing it in the console.