AttributeError: 'TFBertForQuestionAnswering' object has no attribute 'save_pretrained
### System Info

```shell
I coding in Colab
```


### Who can help?

AttributeError                            Traceback (most recent call last)
<ipython-input-64-1a5b1a678c55> in <module>()
----> 4 model.save_pretrained('model_bert_20220609.pt')

AttributeError: 'TFBertForQuestionAnswering' object has no attribute 'save_pretrained

### Information

- [ ] The official example scripts
- [X] My own modified scripts

### Tasks

- [X] An officially supported task in the `examples` folder (such as GLUE/SQuAD, ...)
- [ ] My own task or dataset (give details below)

### Reproduction

from transformers import BertTokenizerFast
 
model = TFBertModel.from_pretrained("klue/bert-base",  from_pt = True)
optimizer = tf.keras.optimizers.Adam(learning_rate=5e-5)
loss = tf.keras.losses.SparseCategoricalCrossentropy(from_logits=False)
model.compile(optimizer=optimizer, loss=loss)

history = model.fit(
    x_train,
    y_train,
    epochs = 5,
    verbose = 1,
    batch_size = 16,
)

model.save_pretrained('model_bert_20220609.pt')

### Expected behavior

```shell
I want to save my trainned models step by steps but it is not saved.
How can I load and save?
Thank you.
```

I am sorry, I am new for git bug issue menu.
but I have no idea about [save_pretrained]<|||||>I saw https://huggingface.co/blog/tf-serving

this guide was used save_pretrained function.
`from transformers import TFBertForSequenceClassification

model = TFBertForSequenceClassification.from_pretrained("nateraw/bert-base-uncased-imdb", from_pt=True)

model.save_pretrained("my_model", saved_model=True)`

and I check the code about class
`https://github.com/huggingface/transformers/blob/3f936df66287f557c6528912a9a68d7850913b9b/src/transformers/models/bert/modeling_tf_bert.py`

I really really thinking about it.no problem for save_pretrained.

Why save_pretrained is not no attribute? I think it is bugs.<|||||>After 2 days of analysis, I found that there is a difference between the original file on github and the library I received.

The hugging face lib I received was the wrong file, and the class was a completely different model with the same name.<|||||>
I deleted the file and got a clone of github again to solve it.