src/transformers/data/metrics/squad_metrics.py/apply_no_ans_threshold
def apply_no_ans_threshold(scores, na_probs, qid_to_has_ans, na_prob_thresh):
    new_scores = {}
    for qid, s in scores.items():
        pred_na = na_probs[qid] > na_prob_thresh
        if pred_na:
            new_scores[qid] = float(not qid_to_has_ans[qid])
        else:
            new_scores[qid] = s
    return new_scores