Thank you for letting me know that my FastAI was not updated.
I am on GCP, and I finally found the issue. I have been updating my FastAI library using the command below, which in my newbie mind, would have updated all the libraries as confirmed by the message returned below.
Turns out that the FastAI library was only updated to version 1.0.30 (something like that), and I followed the instructions [here], (sudo /opt/anaconda3/bin/conda install fastai -c fastai -c pytorch -c conda-forge)(Update fastai with conda doesn't update to the latest version - #17 by willismar) to update to the latest and the get_preds(ds_type= DatasetType.Fix `) works now.
jupyter@fastai-sg:~$ sudo /opt/anaconda3/bin/conda install -c fastai fastai
Collecting package metadata: done
Solving environment: doneAll requested packages already installed.