Splice expects first index as numeric,
splice(n,x); //n and x are numeric here
It will start removing values from array starting at index n and remove x values after index n.
Now if n is not numeric but a key
then no need of x because x can move pointer forward in a numeric-indexed array
only not associative array. So removing x from splice(n,x) will make function similar to splice(key) etc and so it will work fine.