Fix examples of loading pretrained models in docstring
Author: FeiWang96
Pull request: yes


Comments:
# [Codecov](https://codecov.io/gh/huggingface/pytorch-transformers/pull/973?src=pr&el=h1) Report
> Merging [#973](https://codecov.io/gh/huggingface/pytorch-transformers/pull/973?src=pr&el=desc) into [master](https://codecov.io/gh/huggingface/pytorch-transformers/commit/4fc9f9ef54e2ab250042c55b55a2e3c097858cb7?src=pr&el=desc) will **not change** coverage.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/huggingface/pytorch-transformers/pull/973/graphs/tree.svg?width=650&token=9qOlN6Hb1c&height=150&src=pr)](https://codecov.io/gh/huggingface/pytorch-transformers/pull/973?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master     #973   +/-   ##
=======================================
  Coverage   79.16%   79.16%           
=======================================
  Files          38       38           
  Lines        6406     6406           
=======================================
  Hits         5071     5071           
  Misses       1335     1335
```


| [Impacted Files](https://codecov.io/gh/huggingface/pytorch-transformers/pull/973?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pytorch\_transformers/modeling\_transfo\_xl.py](https://codecov.io/gh/huggingface/pytorch-transformers/pull/973/diff?src=pr&el=tree#diff-cHl0b3JjaF90cmFuc2Zvcm1lcnMvbW9kZWxpbmdfdHJhbnNmb194bC5weQ==) | `57.53% <ø> (ø)` | :arrow_up: |
| [pytorch\_transformers/modeling\_xlnet.py](https://codecov.io/gh/huggingface/pytorch-transformers/pull/973/diff?src=pr&el=tree#diff-cHl0b3JjaF90cmFuc2Zvcm1lcnMvbW9kZWxpbmdfeGxuZXQucHk=) | `79.01% <ø> (ø)` | :arrow_up: |
| [pytorch\_transformers/modeling\_xlm.py](https://codecov.io/gh/huggingface/pytorch-transformers/pull/973/diff?src=pr&el=tree#diff-cHl0b3JjaF90cmFuc2Zvcm1lcnMvbW9kZWxpbmdfeGxtLnB5) | `86.66% <ø> (ø)` | :arrow_up: |
| [pytorch\_transformers/modeling\_bert.py](https://codecov.io/gh/huggingface/pytorch-transformers/pull/973/diff?src=pr&el=tree#diff-cHl0b3JjaF90cmFuc2Zvcm1lcnMvbW9kZWxpbmdfYmVydC5weQ==) | `87.98% <ø> (ø)` | :arrow_up: |
| [pytorch\_transformers/modeling\_openai.py](https://codecov.io/gh/huggingface/pytorch-transformers/pull/973/diff?src=pr&el=tree#diff-cHl0b3JjaF90cmFuc2Zvcm1lcnMvbW9kZWxpbmdfb3BlbmFpLnB5) | `74.76% <ø> (ø)` | :arrow_up: |
| [pytorch\_transformers/modeling\_gpt2.py](https://codecov.io/gh/huggingface/pytorch-transformers/pull/973/diff?src=pr&el=tree#diff-cHl0b3JjaF90cmFuc2Zvcm1lcnMvbW9kZWxpbmdfZ3B0Mi5weQ==) | `75.84% <ø> (ø)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/huggingface/pytorch-transformers/pull/973?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/pytorch-transformers/pull/973?src=pr&el=footer). Last update [4fc9f9e...6ec1ee9](https://codecov.io/gh/huggingface/pytorch-transformers/pull/973?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).


# [Codecov](https://codecov.io/gh/huggingface/pytorch-transformers/pull/973?src=pr&el=h1) Report
> Merging [#973](https://codecov.io/gh/huggingface/pytorch-transformers/pull/973?src=pr&el=desc) into [master](https://codecov.io/gh/huggingface/pytorch-transformers/commit/4fc9f9ef54e2ab250042c55b55a2e3c097858cb7?src=pr&el=desc) will **not change** coverage.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/huggingface/pytorch-transformers/pull/973/graphs/tree.svg?width=650&token=9qOlN6Hb1c&height=150&src=pr)](https://codecov.io/gh/huggingface/pytorch-transformers/pull/973?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master     #973   +/-   ##
=======================================
  Coverage   79.16%   79.16%           
=======================================
  Files          38       38           
  Lines        6406     6406           
=======================================
  Hits         5071     5071           
  Misses       1335     1335
```


| [Impacted Files](https://codecov.io/gh/huggingface/pytorch-transformers/pull/973?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pytorch\_transformers/modeling\_transfo\_xl.py](https://codecov.io/gh/huggingface/pytorch-transformers/pull/973/diff?src=pr&el=tree#diff-cHl0b3JjaF90cmFuc2Zvcm1lcnMvbW9kZWxpbmdfdHJhbnNmb194bC5weQ==) | `57.53% <ø> (ø)` | :arrow_up: |
| [pytorch\_transformers/modeling\_xlnet.py](https://codecov.io/gh/huggingface/pytorch-transformers/pull/973/diff?src=pr&el=tree#diff-cHl0b3JjaF90cmFuc2Zvcm1lcnMvbW9kZWxpbmdfeGxuZXQucHk=) | `79.01% <ø> (ø)` | :arrow_up: |
| [pytorch\_transformers/modeling\_xlm.py](https://codecov.io/gh/huggingface/pytorch-transformers/pull/973/diff?src=pr&el=tree#diff-cHl0b3JjaF90cmFuc2Zvcm1lcnMvbW9kZWxpbmdfeGxtLnB5) | `86.66% <ø> (ø)` | :arrow_up: |
| [pytorch\_transformers/modeling\_bert.py](https://codecov.io/gh/huggingface/pytorch-transformers/pull/973/diff?src=pr&el=tree#diff-cHl0b3JjaF90cmFuc2Zvcm1lcnMvbW9kZWxpbmdfYmVydC5weQ==) | `87.98% <ø> (ø)` | :arrow_up: |
| [pytorch\_transformers/modeling\_openai.py](https://codecov.io/gh/huggingface/pytorch-transformers/pull/973/diff?src=pr&el=tree#diff-cHl0b3JjaF90cmFuc2Zvcm1lcnMvbW9kZWxpbmdfb3BlbmFpLnB5) | `74.76% <ø> (ø)` | :arrow_up: |
| [pytorch\_transformers/modeling\_gpt2.py](https://codecov.io/gh/huggingface/pytorch-transformers/pull/973/diff?src=pr&el=tree#diff-cHl0b3JjaF90cmFuc2Zvcm1lcnMvbW9kZWxpbmdfZ3B0Mi5weQ==) | `75.84% <ø> (ø)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/huggingface/pytorch-transformers/pull/973?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/pytorch-transformers/pull/973?src=pr&el=footer). Last update [4fc9f9e...6ec1ee9](https://codecov.io/gh/huggingface/pytorch-transformers/pull/973?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).


Great! Thanks a lot @FeiWang96!