AttributeError: 'DataLoader' object has no attribute 'device'

Here is a link to my notebook https://www.kaggle.com/sarthaksshukla/cnn-with-pytorch. When I try to run learner.lr_find(), learner being the FastAI's Learner, it shows the error shown above. Please help. I am running this notebook on Kaggle, therefore I do not know the versions of the PyTorch or FastAI that are currently being used.