def test_from_values(self):
        st = Stack.from_values()
        self.assertEqual(len(st), 0)

        st = Stack.from_values(11, 22)
        self.assertEqual(len(st), 2)
        self.assertEqual(st.top(), 22)
 def test_top(self):
     st = Stack.from_values(11, 22)
     self.assertEqual(st.top(), 22)
     st.pop()
     self.assertEqual(st.top(), 11)
     st.pop()