noamaanMulla-03/transformers-issues huggingface dataset:
model cards for both aubmindlab/bert-base-arabert models
Author: WissamAntoun
Pull request: yes
Labels: name: model card


Comments:
# [Codecov](https://codecov.io/gh/huggingface/transformers/pull/3113?src=pr&el=h1) Report
> Merging [#3113](https://codecov.io/gh/huggingface/transformers/pull/3113?src=pr&el=desc) into [master](https://codecov.io/gh/huggingface/transformers/commit/e9e6efdc452b74947d40a5a2e8af2fc444c63b5b?src=pr&el=desc) will **decrease** coverage by `0.51%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/huggingface/transformers/pull/3113/graphs/tree.svg?width=650&token=9qOlN6Hb1c&height=150&src=pr)](https://codecov.io/gh/huggingface/transformers/pull/3113?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master    #3113      +/-   ##
==========================================
- Coverage   78.35%   77.84%   -0.52%     
==========================================
  Files          98       98              
  Lines       16422    16422              
==========================================
- Hits        12868    12784      -84     
- Misses       3554     3638      +84
```


| [Impacted Files](https://codecov.io/gh/huggingface/transformers/pull/3113?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [src/transformers/data/processors/squad.py](https://codecov.io/gh/huggingface/transformers/pull/3113/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9kYXRhL3Byb2Nlc3NvcnMvc3F1YWQucHk=) | `28.89% <0%> (-27.6%)` | :arrow_down: |
| [src/transformers/modeling\_utils.py](https://codecov.io/gh/huggingface/transformers/pull/3113/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ191dGlscy5weQ==) | `94.61% <0%> (+0.15%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/huggingface/transformers/pull/3113?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/huggingface/transformers/pull/3113?src=pr&el=footer). Last update [e9e6efd...07a4c8b](https://codecov.io/gh/huggingface/transformers/pull/3113?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
include tf gpt2 tests for attn mask and past variable
Author: patrickvonplaten
Pull request: yes

Test TF GPT2 for correct behavior regarding the past and attn mask variable. Translated code from torch to TF 2.0. 



Comments:
# [Codecov](https://codecov.io/gh/huggingface/transformers/pull/3122?src=pr&el=h1) Report
> Merging [#3122](https://codecov.io/gh/huggingface/transformers/pull/3122?src=pr&el=desc) into [master](https://codecov.io/gh/huggingface/transformers/commit/34de670dbe70a9ead31d0692ad9dc726d3ea4edb?src=pr&el=desc) will **decrease** coverage by `0.04%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/huggingface/transformers/pull/3122/graphs/tree.svg?width=650&token=9qOlN6Hb1c&height=150&src=pr)](https://codecov.io/gh/huggingface/transformers/pull/3122?src=pr&el=tree)

```diff
@@            Coverage Diff            @@
##           master   #3122      +/-   ##
=========================================
- Coverage   77.84%   77.8%   -0.05%     
=========================================
  Files          98      98              
  Lines       16422   16422              
=========================================
- Hits        12784   12777       -7     
- Misses       3638    3645       +7
```


| [Impacted Files](https://codecov.io/gh/huggingface/transformers/pull/3122?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [src/transformers/tokenization\_utils.py](https://codecov.io/gh/huggingface/transformers/pull/3122/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy90b2tlbml6YXRpb25fdXRpbHMucHk=) | `90.87% <0%> (-0.86%)` | :arrow_down: |
| [src/transformers/modeling\_utils.py](https://codecov.io/gh/huggingface/transformers/pull/3122/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ191dGlscy5weQ==) | `94.45% <0%> (-0.16%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/huggingface/transformers/pull/3122?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/huggingface/transformers/pull/3122?src=pr&el=footer). Last update [34de670...1305f35](https://codecov.io/gh/huggingface/transformers/pull/3122?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
Create README.md
Author: mrm8488
Pull request: yes
Labels: name: model card

- Thumbnail is not set!

Comments:
You have to add the thumbnail

# [Codecov](https://codecov.io/gh/huggingface/transformers/pull/3111?src=pr&el=h1) Report
> Merging [#3111](https://codecov.io/gh/huggingface/transformers/pull/3111?src=pr&el=desc) into [master](https://codecov.io/gh/huggingface/transformers/commit/e9e6efdc452b74947d40a5a2e8af2fc444c63b5b?src=pr&el=desc) will **decrease** coverage by `0.52%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/huggingface/transformers/pull/3111/graphs/tree.svg?width=650&token=9qOlN6Hb1c&height=150&src=pr)](https://codecov.io/gh/huggingface/transformers/pull/3111?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master    #3111      +/-   ##
==========================================
- Coverage   78.35%   77.83%   -0.53%     
==========================================
  Files          98       98              
  Lines       16422    16422              
==========================================
- Hits        12868    12782      -86     
- Misses       3554     3640      +86
```


| [Impacted Files](https://codecov.io/gh/huggingface/transformers/pull/3111?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [src/transformers/data/processors/squad.py](https://codecov.io/gh/huggingface/transformers/pull/3111/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9kYXRhL3Byb2Nlc3NvcnMvc3F1YWQucHk=) | `28.89% <0%> (-27.6%)` | :arrow_down: |
| [src/transformers/modeling\_utils.py](https://codecov.io/gh/huggingface/transformers/pull/3111/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ191dGlscy5weQ==) | `94.29% <0%> (-0.16%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/huggingface/transformers/pull/3111?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/huggingface/transformers/pull/3111?src=pr&el=footer). Last update [e9e6efd...3060b8c](https://codecov.io/gh/huggingface/transformers/pull/3111?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).


Hi, Julien. Can you add the default thumbnail you usually add to models? (name of the model + Huggingface logo)
Create README.md
Author: mrm8488
Pull request: yes
Labels: name: model card


Comments:
# [Codecov](https://codecov.io/gh/huggingface/transformers/pull/3127?src=pr&el=h1) Report
> Merging [#3127](https://codecov.io/gh/huggingface/transformers/pull/3127?src=pr&el=desc) into [master](https://codecov.io/gh/huggingface/transformers/commit/ec60e0ae7a88e46ac2bfbf6234d14381a01be06a?src=pr&el=desc) will **increase** coverage by `0.04%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/huggingface/transformers/pull/3127/graphs/tree.svg?width=650&token=9qOlN6Hb1c&height=150&src=pr)](https://codecov.io/gh/huggingface/transformers/pull/3127?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master    #3127      +/-   ##
==========================================
+ Coverage   77.79%   77.84%   +0.04%     
==========================================
  Files          98       98              
  Lines       16422    16422              
==========================================
+ Hits        12776    12783       +7     
+ Misses       3646     3639       -7
```


| [Impacted Files](https://codecov.io/gh/huggingface/transformers/pull/3127?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [src/transformers/modeling\_utils.py](https://codecov.io/gh/huggingface/transformers/pull/3127/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ191dGlscy5weQ==) | `94.45% <0%> (+0.15%)` | :arrow_up: |
| [src/transformers/tokenization\_utils.py](https://codecov.io/gh/huggingface/transformers/pull/3127/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy90b2tlbml6YXRpb25fdXRpbHMucHk=) | `91.72% <0%> (+0.85%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/huggingface/transformers/pull/3127?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/huggingface/transformers/pull/3127?src=pr&el=footer). Last update [ec60e0a...5e9f364](https://codecov.io/gh/huggingface/transformers/pull/3127?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
CamembertForQuestionAnswering
Author: giuliorav
Pull request: no
Labels: name: wontfix

Hi,
is it possibile tu add _CamembertForQuestionAnswering_ class that extend _RobertaForQuestionAnswering_ into **src/transformers/modeling_camembert.py**, **src/transformers/__init__.py** and **examples/run_squad.py** ?

I had to manually force it in order to execute _run_squad.py_ with a CamemBERT-like network.


Thanks.

Comments:
This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.
Add beam search to generation tf 2 0
Author: patrickvonplaten
Pull request: yes

Add beam search to the TF generate function as it is done for torch at the moment. Use same TF syntax that was used in PR #3063 

EDIT: Also included a quick fix that `TF GPT2 past.shape == PT GPT2 past.shape`

Comments:
# [Codecov](https://codecov.io/gh/huggingface/transformers/pull/3118?src=pr&el=h1) Report
> Merging [#3118](https://codecov.io/gh/huggingface/transformers/pull/3118?src=pr&el=desc) into [master](https://codecov.io/gh/huggingface/transformers/commit/34de670dbe70a9ead31d0692ad9dc726d3ea4edb?src=pr&el=desc) will **increase** coverage by `0.1%`.
> The diff coverage is `84.51%`.

[![Impacted file tree graph](https://codecov.io/gh/huggingface/transformers/pull/3118/graphs/tree.svg?width=650&token=9qOlN6Hb1c&height=150&src=pr)](https://codecov.io/gh/huggingface/transformers/pull/3118?src=pr&el=tree)

```diff
@@            Coverage Diff            @@
##           master    #3118     +/-   ##
=========================================
+ Coverage   77.84%   77.95%   +0.1%     
=========================================
  Files          98       98             
  Lines       16422    16561    +139     
=========================================
+ Hits        12784    12910    +126     
- Misses       3638     3651     +13
```


| [Impacted Files](https://codecov.io/gh/huggingface/transformers/pull/3118?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [src/transformers/modeling\_tf\_gpt2.py](https://codecov.io/gh/huggingface/transformers/pull/3118/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ190Zl9ncHQyLnB5) | `96.14% <100%> (ø)` | :arrow_up: |
| [src/transformers/modeling\_tf\_ctrl.py](https://codecov.io/gh/huggingface/transformers/pull/3118/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ190Zl9jdHJsLnB5) | `99.57% <100%> (ø)` | :arrow_up: |
| [src/transformers/modeling\_tf\_utils.py](https://codecov.io/gh/huggingface/transformers/pull/3118/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ190Zl91dGlscy5weQ==) | `91.29% <84.1%> (-0.28%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/huggingface/transformers/pull/3118?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/huggingface/transformers/pull/3118?src=pr&el=footer). Last update [34de670...7a89a3e](https://codecov.io/gh/huggingface/transformers/pull/3118?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).


Good to merge for me! @LysandreJik @thomwolf 

This is really cool, thanks a lot @patrickvonplaten 

Cc @minimaxir
Only use F.gelu for torch >=1.4.0
Author: sshleifer
Pull request: yes


Comments:
# [Codecov](https://codecov.io/gh/huggingface/transformers/pull/2955?src=pr&el=h1) Report
> Merging [#2955](https://codecov.io/gh/huggingface/transformers/pull/2955?src=pr&el=desc) into [master](https://codecov.io/gh/huggingface/transformers/commit/3e98f27e4a9bb0ac3d0fe24b94d30da42cdae8a7?src=pr&el=desc) will **decrease** coverage by `<.01%`.
> The diff coverage is `66.66%`.

[![Impacted file tree graph](https://codecov.io/gh/huggingface/transformers/pull/2955/graphs/tree.svg?width=650&token=9qOlN6Hb1c&height=150&src=pr)](https://codecov.io/gh/huggingface/transformers/pull/2955?src=pr&el=tree)

```diff
@@            Coverage Diff            @@
##           master   #2955      +/-   ##
=========================================
- Coverage    76.1%   76.1%   -0.01%     
=========================================
  Files          98      98              
  Lines       15946   15948       +2     
=========================================
+ Hits        12136   12137       +1     
- Misses       3810    3811       +1
```


| [Impacted Files](https://codecov.io/gh/huggingface/transformers/pull/2955?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [src/transformers/activations.py](https://codecov.io/gh/huggingface/transformers/pull/2955/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9hY3RpdmF0aW9ucy5weQ==) | `87.5% <66.66%> (-5.36%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/huggingface/transformers/pull/2955?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/huggingface/transformers/pull/2955?src=pr&el=footer). Last update [3e98f27...49c66bd](https://codecov.io/gh/huggingface/transformers/pull/2955?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
Masked LM implementation details
Author: luozhouyang
Pull request: no
Labels: name: TensorFlow

name: Core: Modeling

I read the source code of `TFBertMLMHead`, it seems that, this layer just predict the whole sequence, rather than predict the `MASKED` tokens.

`TFBertMLMHead` just do these things:

* transform the `hidden state` from the last encoder layer
* `predictions = tf.matmul(hidden_state, input_embedding_matrix)`, with shape (batch_size, sequence_length, vocab_size)
* return the `predictions` to calculate loss

The inputs are simply the `hidden state` of the last encoder layer.

But the implemenmtation from [google-research/bert](https://github.com/google-research/bert/blob/cc7051dc592802f501e8a6f71f8fb3cf9de95dc9/run_pretraining.py#L240) needs extra inputs `masked_lm_positions` and `masked_lm_weights`, and then use these inputs to calculate the masked lm loss.

So, does the `TFBertMLMHead` miss something?


Comments:
The method from google-research/bert you're showing returns the loss. We don't return the loss with `TFBertForMaskedLM`, we return the output distribution over the vocabulary. You can then use this output distribution to compute the loss, with a cross entropy loss for example.

I see, thanks.
Confusion about the target_mapping parameter of the xlnet model
Author: neoql
Pull request: no
Labels: name: wontfix

Why code at https://github.com/huggingface/transformers/blob/f75bf05ce6a05ef316363de129c29f2e00cacd7b/src/transformers/modeling_xlnet.py#L1029 is ` target_mapping[0, 0, -1] = 1.0`, i think it should be `  target_mapping[:, :, -1] = 1.0`

And I‘m confused about `taget_mapping` parameter, What is the difference between it and the `perm_mask` parameter?


Comments:
This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.
Add model cards for DeepPavlov models
Author: yoptar
Pull request: yes
Labels: name: model card

Sorry about the Cyrillic `с` yesterday.

Comments:
# [Codecov](https://codecov.io/gh/huggingface/transformers/pull/3138?src=pr&el=h1) Report
> Merging [#3138](https://codecov.io/gh/huggingface/transformers/pull/3138?src=pr&el=desc) into [master](https://codecov.io/gh/huggingface/transformers/commit/e9e6efdc452b74947d40a5a2e8af2fc444c63b5b?src=pr&el=desc) will **decrease** coverage by `0.52%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/huggingface/transformers/pull/3138/graphs/tree.svg?width=650&token=9qOlN6Hb1c&height=150&src=pr)](https://codecov.io/gh/huggingface/transformers/pull/3138?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master    #3138      +/-   ##
==========================================
- Coverage   78.35%   77.83%   -0.53%     
==========================================
  Files          98       98              
  Lines       16422    16422              
==========================================
- Hits        12868    12782      -86     
- Misses       3554     3640      +86
```


| [Impacted Files](https://codecov.io/gh/huggingface/transformers/pull/3138?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [src/transformers/data/processors/squad.py](https://codecov.io/gh/huggingface/transformers/pull/3138/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9kYXRhL3Byb2Nlc3NvcnMvc3F1YWQucHk=) | `28.89% <0%> (-27.6%)` | :arrow_down: |
| [src/transformers/modeling\_utils.py](https://codecov.io/gh/huggingface/transformers/pull/3138/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ191dGlscy5weQ==) | `94.29% <0%> (-0.16%)` | :arrow_down: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/huggingface/transformers/pull/3138?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/huggingface/transformers/pull/3138?src=pr&el=footer). Last update [e9e6efd...fe1854d](https://codecov.io/gh/huggingface/transformers/pull/3138?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).


You can also add a link to a thumbnail image from the `thumbnail:` attribute of the YAML front matter metadata, if you want.

Thank you!
ċ in gpt2
Author: weiguowilliam
Pull request: no
Labels: name: Discussion

name: Core: Tokenization

There's a 'ċ' in gpt2.

```
vocab = list(tokenizer_gpt2.encoder.keys())
vocab[198]
```
output: ċ

Based on some examples, I guess it means "with_break". But I can't find this parameter in gpt2 tokenizer document. Can anyone tell me the meaning? thank you.

Comments:
The proper way to decode a value is using the `decode` method:

```py
from transformers import GPT2Tokenizer
tokenizer = GPT2Tokenizer.from_pretrained("gpt2")

tokenizer.decode([198])  # '\n'
```

Some byte indices are shifted in the GPT-2 vocabulary, especially the control characters and characters that resemble whitespace. This is an example, and you can see the method that does it in `~transformers.tokenization_gpt2.bytes_to_unicode`.
Missing `missing_keys` when loading from saved base model checkpoint
Author: LysandreJik
Pull request: no
Labels: name: Core: Modeling

# 🐛 Bug

## Information

If a base model (e.g. `BertModel`, `DistilBertModel`, ...) is saved using `save_pretrained` and a model with an additional head (e.g. `BertForSequenceClassification`, `DistilBertForQuestionAnswering`, ...) is loaded from that checkpoint, it will not detect that it is missing layers.

## To reproduce

Steps to reproduce the behavior:

1. Instantiate base model from configuration or from `from_pretrained`
2. Save model using `save_pretrained`
3. Load checkpoint in model with head
4. No warning is output. Furthermore, if `output_loading_info=True` in step 3), will output `{'missing_keys': [], 'unexpected_keys': [], 'error_msgs': []}`

Here's a reproducible example:

```py
from transformers import BertForSequenceClassification, BertModel, BertConfig

config = BertConfig()
base_model = BertModel(config)
base_model.save_pretrained(directory)

model, loading_info = BertForSequenceClassification.from_pretrained(directory, output_loading_info=True)
print(loading_info)

# {'missing_keys': [], 'unexpected_keys': [], 'error_msgs': []}
# Should output {'missing_keys': ['classifier.weight', 'classifier.bias'], 'unexpected_keys': [], 'error_msgs': []}

```

## Expected behavior

Should detect the missing keys, as it does when loading from a full checkpoint:

```py
from transformers import BertForSequenceClassification

model, loading_info = BertForSequenceClassification.from_pretrained("bert-base-cased", output_loading_info=True)
print(loading_info)

# {'missing_keys': ['classifier.weight', 'classifier.bias'], 'unexpected_keys': ['cls.predictions.bias', 'cls.predictions.transform.dense.weight', 'cls.predictions.transform.dense.bias', 'cls.predictions.decoder.weight', 'cls.seq_relationship.weight', 'cls.seq_relationship.bias', 'cls.predictions.transform.LayerNorm.weight', 'cls.predictions.transform.LayerNorm.bias'], 'error_msgs': []}

```

## Environment info
<!-- You can run the command `python transformers-cli env` and copy-and-paste its output below.
     Don't forget to fill out the missing fields in that output! -->
     
- `transformers` version: master branch
- Platform: Linux-5.5.7-arch1-1-x86_64-with-arch
- Python version: 3.6.10
- PyTorch version (GPU?): 1.4.0 (True)
- Tensorflow version (GPU?): 2.1.0 (True)
- Using GPU in script?: No
- Using distributed or parallel set-up in script?: No


Comments:
wrong 'label2id' and 'id2label' in config when loading from pretrained
Author: daria-pylypenko
Pull request: no

# 🐛 Bug

## Information

Model I am using (Bert, XLNet ...): Bert

Language I am using the model on (English, Chinese ...): English

The problem arises when using:
* [ ] the official example scripts: (give details below)
* [x] my own modified scripts: (give details below)

The tasks I am working on is:
* [ ] an official GLUE/SQUaD task: (give the name)
* [x] my own task or dataset: (give details below)

## To reproduce

Steps to reproduce the behavior:

1. 
```python
from transformers import BertConfig
config = BertConfig.from_pretrained('bert-base-cased', num_labels=3)
print(config.id2label)
```
2. Prints: {0: 'LABEL_0', 1: 'LABEL_1'}


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## Expected behavior

<!-- A clear and concise description of what you would expect to happen. -->

prints {0: 'LABEL_0', 1: 'LABEL_1', 2: 'LABEL_2'}

## Environment info
<!-- You can run the command `python transformers-cli env` and copy-and-paste its output below.
     Don't forget to fill out the missing fields in that output! -->
     
- `transformers` version: 2.5.1
- Platform: Ubuntu 16.04
- Python version: 3.7.6
- PyTorch version (GPU?): 1.4.0
- Using GPU in script?: no
- Using distributed or parallel set-up in script?: no


Comments: