  class TestHanoi(object):
  
      def test_hanoi(self):
          num_disks = 3
          src = Stack()
          buff = Stack()
          dest = Stack()
  
          print('Test: None towers')
 
</s> remove         hanoi(num_disks, None, None, None)
 </s> add         assert_raises(TypeError, hanoi.move_disks, num_disks, None, None, None) </s> remove from nose.tools import assert_equal
 </s> add from nose.tools import assert_equal, assert_raises </s> remove     "        hanoi(num_disks, None, None, None)\n",
 </s> add     "        assert_raises(TypeError, hanoi.move_disks, num_disks, None, None, None)\n",
        hanoi = Hanoi()
  class TestHanoi(object):
  
      def test_hanoi(self):
        hanoi = Hanoi()
          num_disks = 3
          src = Stack()
          buff = Stack()
          dest = Stack()
  
          print('Test: None towers')
keep keep add keep keep keep keep keep keep
 Update hanoi challenge (#121)

Update constraints and test cases.  Move implementation to a class.  Update tests. 
recursion_dynamic/hanoi/test_hanoi.py