input: def print_reverse_array(arr):
      """Prints out the array in reverse order.
      
      >>> print_reverse_array([1, 2, 3])
      3
      2
      1
      >>> print_reverse_array(["a", "b", "c", "d"])
      d
      c
      b
      a
      """
      for i in range(len(arr)-1, -1, -1):
          print(arr[i])
output:     for i in range(len(arr)-1, -1, -1):
          print(arr[i])