Saving and reloading the pretrained model's vocab breaks the tokenizer.

[owos]

Describe the bug

So I picked nvidia/parakeet-ctc-0.6b and I untarred the the .nemo file.
After that, I then loaded the model and changed the the vocab this way:

Steps/Code to reproduce bug

model.change_vocabulary(
            new_tokenizer_dir=vocab_extension_path, new_tokenizer_type="bpe"
        )

where vocab_extension_path = the path of the pretrained model.

Expected behavior
The model's tokenizer is supposed to remain intact and not start generating gibberish because I am just reloading the extact tokenizer that was used to pretrain the model.

Why I need this
I need to replace some tokens in the model's vocab while keeping the order tokens intact. If I cant keep other parts of the tokenizer intact then my replacement of tokens cannot work.

[nithinraok]

It should be path to a tokenizer directory not model.

the directory should contain:

• tokenizer.model
• tokenizer.vocab
• vocab.txt

[owos]

Yes, that's what I'm doing.
Infact, I've been able to edit the pretrained model's tokenizer and changed the tokens inside of it.
What I found out is that just reloading the pretrained tokenizer with the change_vocab method scatters the whole decoding process.