input: Write a function that takes a list of numbers as an input and prints the elements of the array from the end to the beginning. If the input list is empty, do nothing.
  
  assert printArrayReverse([])==None
  assert printArrayReverse([1, 2, 3, 4, 5])=="5 4 3 2 1 "
output: def printArrayReverse(arr):
      if arr:
          print(" ".join(map(str, arr[::-1])))