def test_valid_multiple_types(self): self.assertEqual(is_valid('()[]{}'), True)
def test_valid_paren(self): self.assertEqual(is_valid('()'), True)
def test_unclosed(self): self.assertEqual(is_valid('['), False)
def test_valid_nested(self): self.assertEqual(is_valid('{[]}'), True)
def test_invalid_order(self): self.assertEqual(is_valid('([)]'), False)
def test_invalid_multiple_types(self): self.assertEqual(is_valid('(]'), False)