def test_true_2(self):
     self.assertTrue(double_check('a 11 c d'))
 def test_true(self):
     self.assertTrue(double_check('aabc'))
 def test_false(self):
     self.assertFalse(double_check('abca'))
 def test_false_2(self):
     self.assertFalse(double_check('a b c d e f g h i h k'))
 def test_true_3(self):
     self.assertTrue(double_check('AabBcC'))