Remove support for Python 2
Author: aaugustin
Pull request: yes


Comments:
# [Codecov](https://codecov.io/gh/huggingface/transformers/pull/2270?src=pr&el=h1) Report
> Merging [#2270](https://codecov.io/gh/huggingface/transformers/pull/2270?src=pr&el=desc) into [master](https://codecov.io/gh/huggingface/transformers/commit/b6ea0f43aeb7ff1dcb03658e38bacae1130abd91?src=pr&el=desc) will **increase** coverage by `1.2%`.
> The diff coverage is `86.66%`.

[![Impacted file tree graph](https://codecov.io/gh/huggingface/transformers/pull/2270/graphs/tree.svg?width=650&token=9qOlN6Hb1c&height=150&src=pr)](https://codecov.io/gh/huggingface/transformers/pull/2270?src=pr&el=tree)

```diff
@@            Coverage Diff            @@
##           master    #2270     +/-   ##
=========================================
+ Coverage   73.25%   74.45%   +1.2%     
=========================================
  Files          85       85             
  Lines       14779    14610    -169     
=========================================
+ Hits        10826    10878     +52     
+ Misses       3953     3732    -221
```


| [Impacted Files](https://codecov.io/gh/huggingface/transformers/pull/2270?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [src/transformers/modeling\_camembert.py](https://codecov.io/gh/huggingface/transformers/pull/2270/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ19jYW1lbWJlcnQucHk=) | `100% <ø> (ø)` | :arrow_up: |
| [src/transformers/configuration\_roberta.py](https://codecov.io/gh/huggingface/transformers/pull/2270/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9jb25maWd1cmF0aW9uX3JvYmVydGEucHk=) | `100% <ø> (ø)` | :arrow_up: |
| [src/transformers/tokenization\_distilbert.py](https://codecov.io/gh/huggingface/transformers/pull/2270/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy90b2tlbml6YXRpb25fZGlzdGlsYmVydC5weQ==) | `100% <ø> (ø)` | :arrow_up: |
| [src/transformers/modeling\_tf\_auto.py](https://codecov.io/gh/huggingface/transformers/pull/2270/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ190Zl9hdXRvLnB5) | `32.14% <ø> (-0.41%)` | :arrow_down: |
| [src/transformers/configuration\_distilbert.py](https://codecov.io/gh/huggingface/transformers/pull/2270/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9jb25maWd1cmF0aW9uX2Rpc3RpbGJlcnQucHk=) | `100% <ø> (ø)` | :arrow_up: |
| [src/transformers/modeling\_tf\_utils.py](https://codecov.io/gh/huggingface/transformers/pull/2270/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ190Zl91dGlscy5weQ==) | `93.12% <ø> (-0.04%)` | :arrow_down: |
| [src/transformers/configuration\_ctrl.py](https://codecov.io/gh/huggingface/transformers/pull/2270/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9jb25maWd1cmF0aW9uX2N0cmwucHk=) | `97.05% <ø> (-0.09%)` | :arrow_down: |
| [src/transformers/tokenization\_roberta.py](https://codecov.io/gh/huggingface/transformers/pull/2270/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy90b2tlbml6YXRpb25fcm9iZXJ0YS5weQ==) | `100% <ø> (ø)` | :arrow_up: |
| [src/transformers/tokenization\_ctrl.py](https://codecov.io/gh/huggingface/transformers/pull/2270/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy90b2tlbml6YXRpb25fY3RybC5weQ==) | `96.11% <ø> (-0.08%)` | :arrow_down: |
| [src/transformers/modeling\_tf\_t5.py](https://codecov.io/gh/huggingface/transformers/pull/2270/diff?src=pr&el=tree#diff-c3JjL3RyYW5zZm9ybWVycy9tb2RlbGluZ190Zl90NS5weQ==) | `96.54% <ø> (-0.01%)` | :arrow_down: |
| ... and [66 more](https://codecov.io/gh/huggingface/transformers/pull/2270/diff?src=pr&el=tree-more) | |

------

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> Powered by [Codecov](https://codecov.io/gh/huggingface/transformers/pull/2270?src=pr&el=footer). Last update [b6ea0f4...1a948d7](https://codecov.io/gh/huggingface/transformers/pull/2270?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).