def test_equals_6(self):
     self.assertEqual(captcha('1212'), 6)
 def test_equals_4__2(self):
     self.assertEqual(captcha('12131415'), 4)
 def test_equals_4(self):
     self.assertEqual(captcha('123425'), 4)
 def test_equals_12(self):
     self.assertEqual(captcha('123123'), 12)
 def test_equals_0(self):
     self.assertEqual(captcha('1221'), 0)