input: Write a python function to print an array in reverse order.
  assert printArrayReverse([1, 2, 3, 4, 5]) == "5 4 3 2 1 "
  assert printArrayReverse(['a', 'b', 'c', 'd']) == "d c b a "
  assert printArrayReverse([10, 20, 30]) == "30 20 10 "
output: def printArrayReverse(arr):
      return " ".join(map(str, arr[::-1])) + " "