3. (30 pts) Consider a procedure static void combine (int[] a, int[] b) that multiplies each element of a by the sum of the elements of b; for example, if a = [1, 2, 3] and b = [4, 5], then on return a = [9, 18, 27). What should this procedure do if a orb is null or empty? Give a specification for combine that answers these questions and explain why your specification is a good one