Write a method called swapPairs that accepts an array of integers and swaps the elements at adjacent indexes. That is, elements 0 and 1 are swapped, elements 2 and 3 are swapped, and so on. If the array has an odd length, the final element should be left unmodified. For example, the list [10, 20, 30, 40, 50] should become [20, 10, 40, 30, 50] after a call to your method.