def test_equals(self):
     self.assertEqual(vowel_2_index('this is my string'),
                      'th3s 6s my str15ng')
 def test_equals_3(self):
     self.assertEqual(vowel_2_index(''), '')
 def test_equals_2(self):
     self.assertEqual(vowel_2_index(
         'Codewars is the best site in the world'),
         'C2d4w6rs 10s th15 b18st s23t25 27n th32 w35rld')
 def test_equals(self):
     self.assertEqual(vowel_2_index('this is my string'),
                      'th3s 6s my str15ng')
 def test_equals_3(self):
     self.assertEqual(vowel_2_index(''), '')
 def test_equals_2(self):
     self.assertEqual(
         vowel_2_index('Codewars is the best site in the world'),
         'C2d4w6rs 10s th15 b18st s23t25 27n th32 w35rld')