Fix
# What does this PR do?

Fixes some suggestions not addressed in [this](https://github.com/huggingface/transformers/pull/15085/) pull request.

I've fixed the typo and unnecessary imports, but running `make style` may not allow some parts of the code to stay in the same line.

## Who can review?

@sgugger 
_The documentation is not available anymore as the PR was closed or merged._<|||||>Hello, the `check_code_quality` fails now. Running `make style` will revert all the changes I made to the modeling file, so some parts of the code will not stay in the same line. <|||||>In the previous commit, I removed trailing commas and put the code in the same line, but the check still fails. In the next commit, I'll run `make style`.<|||||>Thanks again!