def test_identifies_valid_sequence(self):
     self.assertTrue(is_balanced('()'))
     self.assertTrue(is_balanced('()(())'))
 def test_identifies_right_imbalance(self):
     self.assertFalse(is_balanced('())'))
 def test_identifies_left_imbalance(self):
     self.assertFalse(is_balanced('(()'))
 def test_identifies_valid_sequence(self):
     self.assertTrue(is_balanced('()'))
     self.assertTrue(is_balanced('()(())'))
 def test_identifies_right_imbalance(self):
     self.assertFalse(is_balanced('())'))
 def test_identifies_left_imbalance(self):
     self.assertFalse(is_balanced('(()'))