more general approach

src/transformers/convert_slow_tokenizer.py

@@ -1391,10 +1391,6 @@ class LlamaConverter(SpmConverter):
                     AddedToken(self.original_tokenizer.convert_ids_to_tokens(2), normalized=False, special=True),
                 ]
             )
-            user_defined_symbols = [
-                AddedToken(token, normalized=True, special=False) for token in proto.trainer_spec.user_defined_symbols
-            ]
-            tokenizer.add_tokens(user_defined_symbols)
         else:
             raise Exception(
                 "You're trying to run a `Unigram` model but you're file was trained with a different algorithm"