Hi Ken,
I retrained the model on SQuAD 2.0. But there is no output file (prediction.json) for the initial dev set predictions. See below image. As such, I couldn't run the script:
python $SQUAD_DIR/evaluate-v2.0.py $SQUAD_DIR/dev-v2.0.json ./squad/predictions.json --na-prob-file ./squad/null_odds.json
Any chance you can share some insights?

Thanks a lot.
Luke