Question on question_answering.ipynb

[sam351]

Hi, Thank you for awesome example notebooks!
I'm reviewing the notebook about question answering.
https://github.com/huggingface/notebooks/blob/master/examples/question_answering.ipynb

In the notebook, you used postprocess_qa_predictions function to post-process the prediction of model.
(The function is defined at 25th cell in the notebook.)
And the function initializes valid_answers list(local var) for each example, not feature.
However, I thought that valid_answers should be initialized for each feature, since certain valid answer for one feature's context might not exist in another feature's context.

Is there anything that I misundertood?

Thank you