def test_exists_ShouldDetectAddedWords(self):
        t = Trie()
        t.add('python', 'value')
        t.add('ada', 'value')

        self.assertTrue(t.exists('python'))
        self.assertTrue(t.exists('ada'))
    def test_exists_ShouldReturnFailOnUnknownWord(self):
        t = Trie()
        t.add('python', 'value')

        self.assertFalse(t.exists('ada'))