squad_convert_examples_to_features does not work with tensorflow
Author: Tialo
Pull request: no

### System Info

- `transformers` version: 4.30.2
- Platform: macOS-13.4-x86_64-i386-64bit
- Python version: 3.10.12
- Huggingface_hub version: 0.15.1
- Safetensors version: 0.3.1
- PyTorch version (GPU?): not installed (NA)
- Tensorflow version (GPU?): 2.12.0 (False)
- Flax version (CPU?/GPU?/TPU?): not installed (NA)
- Jax version: not installed
- JaxLib version: not installed
- Using GPU in script?: No
- Using distributed or parallel set-up in script?: No

### Who can help?

_No response_

### Information

- [X] The official example scripts
- [ ] 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

```python

import tensorflow as tf
from transformers import DistilBertTokenizer, TFDistilBertForQuestionAnswering
from transformers import squad_convert_examples_to_features
from transformers.data.processors.squad import SquadV1Processor
import tensorflow_datasets as tfds


if __name__ == "__main__":
    tfds_examples = tfds.load("squad")
    evaluate = False
    examples = SquadV1Processor().get_examples_from_dataset(tfds_examples, evaluate=evaluate)

    tokenizer = DistilBertTokenizer.from_pretrained('distilbert-base-uncased')
    a, b = squad_convert_examples_to_features(
        examples=examples[:3],
        tokenizer=tokenizer,
        max_seq_length=384,
        doc_stride=128,
        max_query_length=64,
        is_training=not evaluate,
        return_dataset="tf"
    )
```
This exception occurs when I use return_dataset="tf", otherwise it's fine.

Error: 
```
2023-06-25 19:09:04.152047: W tensorflow/core/framework/op_kernel.cc:1818] INVALID_ARGUMENT: TypeError: `generator` yielded an element that did not match the expected structure. The expected structure was (
{'input_ids': tf.int32, 
'attention_mask': tf.int32, 
'feature_index': tf.int64, 
'qas_id': tf.string}, {...}), 
but the yielded element was (
{'input_ids': [101, 2054, ..., 0], 
'attention_mask': [1, 1, ..., 0], 
'token_type_ids': [0, 0, ..., 0], 
'feature_index': 0, 
'qas_id': '57306bf68ab72b1400f9c4dc'}, {...})
```

As you can see, for some reason there is an unwanted key in generator.
https://github.com/huggingface/transformers/blob/8e164c5400b7b413c7b8fb32e35132001effc970/src/transformers/data/processors/squad.py#L437


Full error:

2023-06-25 19:09:04.152047: W tensorflow/core/framework/op_kernel.cc:1818] INVALID_ARGUMENT: TypeError: `generator` yielded an element that did not match the expected structure. The expected structure was ({'input_ids': tf.int32, 'attention_mask': tf.int32, 'feature_index': tf.int64, 'qas_id': tf.string}, {'start_positions': tf.int64, 'end_positions': tf.int64, 'cls_index': tf.int64, 'p_mask': tf.int32, 'is_impossible': tf.int32}), but the yielded element was ({'input_ids': [101, 2054, 2003, 2028, 2224, 2008, 2052, 5478, 2019, 13438, 2000, 4374, 7755, 1999, 2536, 3971, 2012, 2320, 1029, 102, 1996, 4489, 1999, 1996, 2682, 5876, 2005, 1996, 2553, 1997, 1162, 1027, 1014, 2003, 1996, 3114, 2008, 2087, 5062, 1006, 21670, 3832, 2005, 1996, 2270, 1007, 3594, 7471, 11508, 3989, 1012, 2005, 19278, 2379, 1996, 2598, 1010, 23190, 11508, 3550, 21670, 9015, 16990, 1012, 2005, 2190, 7684, 1996, 4909, 26315, 2005, 2122, 7755, 2024, 10655, 20018, 11508, 3550, 1012, 1999, 2070, 5097, 2073, 1996, 4909, 13438, 2442, 2147, 1999, 2151, 2597, 1010, 2004, 1999, 4684, 11640, 1010, 1996, 2918, 2276, 26315, 2224, 3816, 11508, 3989, 1010, 2107, 2004, 7399, 11508, 3989, 2012, 2019, 6466, 1006, 2007, 2119, 7471, 1998, 9876, 6177, 1007, 2030, 8206, 11508, 3989, 1012, 102, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], 'attention_mask': [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], 'token_type_ids': [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], 'feature_index': 0, 'qas_id': '57306bf68ab72b1400f9c4dc'}, {'start_positions': 94, 'end_positions': 95, 'cls_index': 0, 'p_mask': [0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1], 'is_impossible': False}).
Traceback (most recent call last):

  File "/Users/user/Desktop/transformers_test/venv/lib/python3.10/site-packages/tensorflow/python/data/ops/from_generator_op.py", line 204, in generator_py_func
    flattened_values = nest.flatten_up_to(output_types, values)

  File "/Users/user/Desktop/transformers_test/venv/lib/python3.10/site-packages/tensorflow/python/data/util/nest.py", line 377, in flatten_up_to
    assert_shallow_structure(shallow_tree, input_tree)

  File "/Users/user/Desktop/transformers_test/venv/lib/python3.10/site-packages/tensorflow/python/data/util/nest.py", line 304, in assert_shallow_structure
    assert_shallow_structure(shallow_branch, input_branch,

  File "/Users/user/Desktop/transformers_test/venv/lib/python3.10/site-packages/tensorflow/python/data/util/nest.py", line 289, in assert_shallow_structure
    raise ValueError(

ValueError: The two structures don't have the same sequence length. Input structure has length 5, while shallow structure has length 4.


The above exception was the direct cause of the following exception:


Traceback (most recent call last):

  File "/Users/user/Desktop/transformers_test/venv/lib/python3.10/site-packages/tensorflow/python/ops/script_ops.py", line 267, in __call__
    ret = func(*args)

  File "/Users/user/Desktop/transformers_test/venv/lib/python3.10/site-packages/tensorflow/python/autograph/impl/api.py", line 642, in wrapper
    return func(*args, **kwargs)

  File "/Users/user/Desktop/transformers_test/venv/lib/python3.10/site-packages/tensorflow/python/data/ops/from_generator_op.py", line 206, in generator_py_func
    raise TypeError(


### Expected behavior

There would be no error. 

Comments:
This is not a maintained part of the library anyore, we use `datasets` for the preprocessing, you can check the QA example [here](https://github.com/huggingface/transformers/blob/main/examples/tensorflow/question-answering/run_qa.py).