input: def print_reverse_array(arr):
      """
      Print out an array backwards.
      
      >>> print_reverse_array([1, 2, 3, 4])
      4
      3
      2
      1
      >>> print_reverse_array(['apple', 'banana', 'cherry'])
      cherry
      banana
      apple
      """
output:     for i in range(len(arr) - 1, -1, -1):
          print(arr[i])