input: Write a function to print out an array in reverse order.
  def print_reverse_array(arr):
   for i in range(len(arr)-1, -1, -1): 
    print(arr[i])
  assert print_reverse_array([1, 2, 3, 4, 5])==None
  assert print_reverse_array(['a', 'b', 'c'])==None
  assert print_reverse_array([])==None
output: def print_reverse_array(arr):
   for i in range(len(arr)-1, -1, -1): 
    print(arr[i])