input: 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([10, 20, 30]) == None
  assert print_reverse_array([]) == None
  assert print_reverse_array([-1, -2, -3]) == None
output:     return None