Fix typo
# [Codecov](https://codecov.io/gh/huggingface/transformers/pull/2855?src=pr&el=h1) Report
> Merging [#2855](https://codecov.io/gh/huggingface/transformers/pull/2855?src=pr&el=desc) into [master](https://codecov.io/gh/huggingface/transformers/commit/925a13ced1e155ea7e55e14e177a7b5ae7ad174c?src=pr&el=desc) will **not change** coverage.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/huggingface/transformers/pull/2855/graphs/tree.svg?width=650&token=9qOlN6Hb1c&height=150&src=pr)](https://codecov.io/gh/huggingface/transformers/pull/2855?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master    #2855   +/-   ##
=======================================
  Coverage   75.06%   75.06%           
=======================================
  Files          94       94           
  Lines       15287    15287           
=======================================
  Hits        11475    11475           
  Misses       3812     3812
```



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